By JBradwell


2011-02-18 12:53:10 8 Comments

Is there any way to select/manipulate CSS pseudo-elements such as ::before and ::after (and the old version with one semi-colon) using jQuery?

For example, my stylesheet has the following rule:

.span::after{ content:'foo' }

How can I change 'foo' to 'bar' using jQuery?

22 comments

@Coding_snakeZ 2019-11-12 09:32:18

I have something different stuff for you which is easy and effective.

    <style> 
    .case-after:after { // set your properties here like eg: 
        color:#3fd309 !important; 
     } 
     .case-before:before { // set your properties here like eg: 
        color:#151715 !important; 
     }
 </style>
  // case for after
    $('#button-id').on('click', function() {
        $(".target-div").toggleClass('case-after');
    });

     // case for before
    $('#button-id').on('click', function() {
        $(".target-div").toggleClass('case-before');
    });

@Temani Afif 2018-04-02 21:15:51

We can also rely on custom properties (aka CSS variables) in order to manipulate pseudo-element. We can read in the specification that:

Custom properties are ordinary properties, so they can be declared on any element, are resolved with the normal inheritance and cascade rules, can be made conditional with @media and other conditional rules, can be used in HTML’s style attribute, can be read or set using the CSSOM, etc.

Considering this, the idea is to define the custom property within the element and the pseudo-element will simply inherit it; thus we can easily modify it.

1) Using inline style:

.box:before {
  content:var(--content,"I am a before element");
  color:var(--color, red);
  font-size:25px;
}
<div class="box"></div>
<div class="box" style="--color:blue;--content:'I am a blue element'"></div>
<div class="box" style="--color:black"></div>
<div class="box" style="--color:#f0f;--content:'another element'"></div>

2) Using CSS and classes

.box:before {
  content:var(--content,"I am a before element");
  color:var(--color, red);
  font-size:25px;
}

.blue {
  --color:blue;
  --content:'I am a blue element';
}
.black {
  --color:black;
}
<div class="box"></div>
<div class="box black" ></div>
<div class="box blue"></div>

3) Using javascript

document.querySelectorAll('.box')[0].style.setProperty("--color", "blue");
document.querySelectorAll('.box')[1].style.setProperty("--content", "'I am another element'");
.box:before {
  content:var(--content,"I am a before element");
  color:var(--color, red);
  font-size:25px;
}
<div class="box"></div>
<div class="box"></div>

4) Using jQuery

$('.box').eq(0).css("--color", "blue");
/* the css() function with custom properties works only with a jQuery vesion >= 3.x
   with older version we can use style attribute to set the value. Simply pay
   attention if you already have inline style defined! 
*/
$('.box').eq(1).attr("style","--color:#f0f");
.box:before {
  content:"I am a before element";
  color:var(--color, red);
  font-size:25px;
}
<script src="https://code.jquery.com/jquery-3.3.1.min.js"></script>
<div class="box"></div>
<div class="box"></div>
<div class="box"></div>


It can also be used with complex values:

.box {
  --c:"content";
  --b:linear-gradient(red,blue);
  --s:20px;
  --p:0 15px;
}

.box:before {
  content: var(--c);
  background:var(--b);
  color:#fff;
  font-size: calc(2 * var(--s) + 5px);
  padding:var(--p);
}
<div class="box"></div>

You may notice that I am considering the syntax var(--c,value) where value is the default value and also called the fallback value.

From the same specification we can read:

The value of a custom property can be substituted into the value of another property with the var() function. The syntax of var() is:

var() = var( <custom-property-name> [, <declaration-value> ]? )

The first argument to the function is the name of the custom property to be substituted. The second argument to the function, if provided, is a fallback value, which is used as the substitution value when the referenced custom property is invalid.

And later:

To substitute a var() in a property’s value:

  1. If the custom property named by the first argument to the var() function is animation-tainted, and the var() function is being used in the animation property or one of its longhands, treat the custom property as having its initial value for the rest of this algorithm.
  2. If the value of the custom property named by the first argument to the var() function is anything but the initial value, replace the var() function by the value of the corresponding custom property.
  3. Otherwise, if the var() function has a fallback value as its second argument, replace the var() function by the fallback value. If there are any var() references in the fallback, substitute them as well.
  4. Otherwise, the property containing the var() function is invalid at computed-value time.

If we don't set the custom property OR we set it to initial OR it contains an invalid value then the fallback value will be used. The use of initial can be helpful in case we want to reset a custom property to its default value.

Related

How to store inherit value inside a CSS custom property (aka CSS variables)?

CSS custom properties (variables) for box model


Please note that CSS variables might not be available in all browsers you consider relevant (e.g. IE 11): https://caniuse.com/#feat=css-variables

@akalata 2018-08-07 15:15:46

Excellent solutions, thanks! I'm stuck with an order version of jQuery (so that wasn't working), but switching to plain JS works like a charm.

@Temani Afif 2018-08-07 15:27:32

@akalata yes, the code require a jQuery version 3.x .. I added more details and another alternative with jQuery ;)

@connexo 2018-09-06 21:20:40

How would this perform in IE 11?

@Temani Afif 2018-09-06 21:25:34

@connexo like any good and modern feature .. it's not supported and will not work caniuse.com/#feat=css-variables

@connexo 2018-09-06 21:27:44

Ofc I knew that and since IE 11 is still very relevant, I missed that piece of information right in the introductory part of your answer.

@Temani Afif 2018-09-06 21:29:40

@connexo you will never find such thing in my answers :) IE doesn't exist in my world ... but feel free to edit and add any information you think relevant.

@connexo 2018-09-06 21:31:58

Added that note in a (not overly) prominent position.

@LebCit 2019-07-19 18:26:31

This answer is an in depth tutorial of relating and modifying pseudo-elements with JavaScript using CSS Variables. Thank you very much for your time and for sharing this extremely valuable technique(s).

@xgqfrms 2019-11-07 06:52:13

awesome solution & css3 var & vanilla javascript

@BananaAcid 2019-02-03 06:55:17

I have created a jQuery plugin to add css-pseudo rules like using .css() for specific elements.

  • plugin code and test case is here
  • use case as simple css image popup here

usage:

$('body')
  .css({
    backgroundColor: 'white'
  })
  .cssPseudo('after', {
    content: 'attr(title) ", you should try to hover the picture, then click it."',
    position: 'absolute',
    top: 20, left: 20  
  })
  .cssPseudo('hover:after', {
    content: '"Now hover the picture, then click it!"'
  });

@Riccardo Volpe 2018-09-17 02:51:51

I made use of variables defined in :root inside CSS to modify the :after (the same applies to :before) pseudo-element, in particular to change the background-color value for a styled anchor defined by .sliding-middle-out:hover:after and the content value for another anchor (#reference) in the following demo that generates random colors by using JavaScript/jQuery:

HTML

<a href="#" id="changeColor" class="sliding-middle-out" title="Generate a random color">Change link color</a>
<span id="log"></span>
<h6>
  <a href="https://stackoverflow.com/a/52360188/2149425" id="reference" class="sliding-middle-out" target="_blank" title="Stack Overflow topic">Reference</a>
</h6>
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script type="text/javascript" src="https://cdn.rawgit.com/davidmerfield/randomColor/master/randomColor.js"></script>

CSS

:root {
    --anchorsFg: #0DAFA4;
}
a, a:visited, a:focus, a:active {
    text-decoration: none;
    color: var(--anchorsFg);
    outline: 0;
    font-style: italic;

    -webkit-transition: color 250ms ease-in-out;
    -moz-transition: color 250ms ease-in-out;
    -ms-transition: color 250ms ease-in-out;
    -o-transition: color 250ms ease-in-out;
    transition: color 250ms ease-in-out;
}
.sliding-middle-out {
    display: inline-block;
    position: relative;
    padding-bottom: 1px;
}
.sliding-middle-out:after {
    content: '';
    display: block;
    margin: auto;
    height: 1px;
    width: 0px;
    background-color: transparent;

    -webkit-transition: width 250ms ease-in-out, background-color 250ms ease-in-out;
    -moz-transition: width 250ms ease-in-out, background-color 250ms ease-in-out;
    -ms-transition: width 250ms ease-in-out, background-color 250ms ease-in-out;
    -o-transition: width 250ms ease-in-out, background-color 250ms ease-in-out;
    transition: width 250ms ease-in-out, background-color 250ms ease-in-out;
}
.sliding-middle-out:hover:after {
    width: 100%;
    background-color: var(--anchorsFg);
    outline: 0;
}
#reference {
  margin-top: 20px;
}
.sliding-middle-out:before {
  content: attr(data-content);
  display: attr(data-display);
}

JS/jQuery

var anchorsFg = randomColor();
$( ".sliding-middle-out" ).hover(function(){
    $( ":root" ).css({"--anchorsFg" : anchorsFg});
});

$( "#reference" ).hover(
 function(){
    $(this).attr("data-content", "Hello World!").attr("data-display", "block").html("");
 },
 function(){
    $(this).attr("data-content", "Reference").attr("data-display", "inline").html("");
 }
);

@BananaAcid 2019-02-03 07:14:01

Support for attr() except in content, is really scarce. You might check caniuse.com for it. :root and css-variables support is better, but still not yet so wide spread since support for it is pretty new. (also check support for it at caniuse.com)

@Orlandster 2018-09-13 09:56:03

I'm always adding my own utils function, which looks like this.

function setPseudoElContent(selector, value) {    
    document.styleSheets[0].addRule(selector, 'content: "' + value + '";');
}

setPseudoElContent('.class::after', 'Hello World!');

or make use of ES6 Features:

const setPseudoElContent = (selector, value) => {    
    document.styleSheets[0].addRule(selector, `content: "${value}";`);
}

setPseudoElContent('.class::after', 'Hello World!');

@BoltClock 2011-02-18 12:56:29

Although they are rendered by browsers through CSS as if they were like other real DOM elements, pseudo-elements themselves are not part of the DOM, because pseudo-elements, as the name implies, are not real elements, and therefore you can't select and manipulate them directly with jQuery (or any JavaScript APIs for that matter, not even the Selectors API). This applies to any pseudo-elements whose styles you're trying to modify with a script, and not just ::before and ::after.

You can only access pseudo-element styles directly at runtime via the CSSOM (think window.getComputedStyle()), which is not exposed by jQuery beyond .css(), a method that doesn't support pseudo-elements either.

You can always find other ways around it, though, for example:

  • Applying the styles to the pseudo-elements of one or more arbitrary classes, then toggling between classes (see seucolega's answer for a quick example) — this is the idiomatic way as it makes use of simple selectors (which pseudo-elements are not) to distinguish between elements and element states, the way they're intended to be used

  • Manipulating the styles being applied to said pseudo-elements, by altering the document stylesheet, which is much more of a hack

@zfb 2017-09-22 08:31:19

Someone else commented on appending to the head element with a full style element and that's not bad if you're only doing it once but if you need to reset it more than once you'll end up with a ton of style elements. So to prevent that I created a blank style element in the head with an id and replace the innerHTML of it like this:

<style id="pseudo"></style>

Then the JavaScript would look like this:

var pseudo = document.getElementById("pseudo");

function setHeight() {
    let height = document.getElementById("container").clientHeight;
    pseudo.innerHTML = `.class:before { height: ${height}px; }`
}

setHeight()

Now in my case I needed this to set the height of a before element based on the height of another and it will change on resize so using this I can run setHeight() every time the window is resized and it will replace the <style> properly.

Hope that helps someone who was stuck trying to do the same thing.

@Yuri 2017-07-31 18:19:08

You can use my plugin for this purpose.

JQuery:

(function() {
  $.pseudoElements = {
    length: 0
  };

  var setPseudoElement = function(parameters) {
    if (typeof parameters.argument === 'object' || (parameters.argument !== undefined && parameters.property !== undefined)) {
      for (var element of parameters.elements.get()) {
        if (!element.pseudoElements) element.pseudoElements = {
          styleSheet: null,
          before: {
            index: null,
            properties: null
          },
          after: {
            index: null,
            properties: null
          },
          id: null
        };

        var selector = (function() {
          if (element.pseudoElements.id !== null) {
            if (Number(element.getAttribute('data-pe--id')) !== element.pseudoElements.id) element.setAttribute('data-pe--id', element.pseudoElements.id);
            return '[data-pe--id="' + element.pseudoElements.id + '"]::' + parameters.pseudoElement;
          } else {
            var id = $.pseudoElements.length;
            $.pseudoElements.length++

              element.pseudoElements.id = id;
            element.setAttribute('data-pe--id', id);

            return '[data-pe--id="' + id + '"]::' + parameters.pseudoElement;
          };
        })();

        if (!element.pseudoElements.styleSheet) {
          if (document.styleSheets[0]) {
            element.pseudoElements.styleSheet = document.styleSheets[0];
          } else {
            var styleSheet = document.createElement('style');

            document.head.appendChild(styleSheet);
            element.pseudoElements.styleSheet = styleSheet.sheet;
          };
        };

        if (element.pseudoElements[parameters.pseudoElement].properties && element.pseudoElements[parameters.pseudoElement].index) {
          element.pseudoElements.styleSheet.deleteRule(element.pseudoElements[parameters.pseudoElement].index);
        };

        if (typeof parameters.argument === 'object') {
          parameters.argument = $.extend({}, parameters.argument);

          if (!element.pseudoElements[parameters.pseudoElement].properties && !element.pseudoElements[parameters.pseudoElement].index) {
            var newIndex = element.pseudoElements.styleSheet.rules.length || element.pseudoElements.styleSheet.cssRules.length || element.pseudoElements.styleSheet.length;

            element.pseudoElements[parameters.pseudoElement].index = newIndex;
            element.pseudoElements[parameters.pseudoElement].properties = parameters.argument;
          };

          var properties = '';

          for (var property in parameters.argument) {
            if (typeof parameters.argument[property] === 'function')
              element.pseudoElements[parameters.pseudoElement].properties[property] = parameters.argument[property]();
            else
              element.pseudoElements[parameters.pseudoElement].properties[property] = parameters.argument[property];
          };

          for (var property in element.pseudoElements[parameters.pseudoElement].properties) {
            properties += property + ': ' + element.pseudoElements[parameters.pseudoElement].properties[property] + ' !important; ';
          };

          element.pseudoElements.styleSheet.addRule(selector, properties, element.pseudoElements[parameters.pseudoElement].index);
        } else if (parameters.argument !== undefined && parameters.property !== undefined) {
          if (!element.pseudoElements[parameters.pseudoElement].properties && !element.pseudoElements[parameters.pseudoElement].index) {
            var newIndex = element.pseudoElements.styleSheet.rules.length || element.pseudoElements.styleSheet.cssRules.length || element.pseudoElements.styleSheet.length;

            element.pseudoElements[parameters.pseudoElement].index = newIndex;
            element.pseudoElements[parameters.pseudoElement].properties = {};
          };

          if (typeof parameters.property === 'function')
            element.pseudoElements[parameters.pseudoElement].properties[parameters.argument] = parameters.property();
          else
            element.pseudoElements[parameters.pseudoElement].properties[parameters.argument] = parameters.property;

          var properties = '';

          for (var property in element.pseudoElements[parameters.pseudoElement].properties) {
            properties += property + ': ' + element.pseudoElements[parameters.pseudoElement].properties[property] + ' !important; ';
          };

          element.pseudoElements.styleSheet.addRule(selector, properties, element.pseudoElements[parameters.pseudoElement].index);
        };
      };

      return $(parameters.elements);
    } else if (parameters.argument !== undefined && parameters.property === undefined) {
      var element = $(parameters.elements).get(0);

      var windowStyle = window.getComputedStyle(
        element, '::' + parameters.pseudoElement
      ).getPropertyValue(parameters.argument);

      if (element.pseudoElements) {
        return $(parameters.elements).get(0).pseudoElements[parameters.pseudoElement].properties[parameters.argument] || windowStyle;
      } else {
        return windowStyle || null;
      };
    } else {
      console.error('Invalid values!');
      return false;
    };
  };

  $.fn.cssBefore = function(argument, property) {
    return setPseudoElement({
      elements: this,
      pseudoElement: 'before',
      argument: argument,
      property: property
    });
  };
  $.fn.cssAfter = function(argument, property) {
    return setPseudoElement({
      elements: this,
      pseudoElement: 'after',
      argument: argument,
      property: property
    });
  };
})();

$(function() {
  $('.element').cssBefore('content', '"New before!"');
});
.element {
  width: 480px;
  margin: 0 auto;
  border: 2px solid red;
}

.element::before {
  content: 'Old before!';
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.1.1/jquery.min.js"></script>

<div class="element"></div>

The values should be specified, as in the normal function of jQuery.css

In addition, you can also get the value of the pseudo-element parameter, as in the normal function of jQuery.css:

console.log( $(element).cssBefore(parameter) );

JS:

(function() {
  document.pseudoElements = {
    length: 0
  };

  var setPseudoElement = function(parameters) {
    if (typeof parameters.argument === 'object' || (parameters.argument !== undefined && parameters.property !== undefined)) {
      if (!parameters.element.pseudoElements) parameters.element.pseudoElements = {
        styleSheet: null,
        before: {
          index: null,
          properties: null
        },
        after: {
          index: null,
          properties: null
        },
        id: null
      };

      var selector = (function() {
        if (parameters.element.pseudoElements.id !== null) {
          if (Number(parameters.element.getAttribute('data-pe--id')) !== parameters.element.pseudoElements.id) parameters.element.setAttribute('data-pe--id', parameters.element.pseudoElements.id);
          return '[data-pe--id="' + parameters.element.pseudoElements.id + '"]::' + parameters.pseudoElement;
        } else {
          var id = document.pseudoElements.length;
          document.pseudoElements.length++

            parameters.element.pseudoElements.id = id;
          parameters.element.setAttribute('data-pe--id', id);

          return '[data-pe--id="' + id + '"]::' + parameters.pseudoElement;
        };
      })();

      if (!parameters.element.pseudoElements.styleSheet) {
        if (document.styleSheets[0]) {
          parameters.element.pseudoElements.styleSheet = document.styleSheets[0];
        } else {
          var styleSheet = document.createElement('style');

          document.head.appendChild(styleSheet);
          parameters.element.pseudoElements.styleSheet = styleSheet.sheet;
        };
      };

      if (parameters.element.pseudoElements[parameters.pseudoElement].properties && parameters.element.pseudoElements[parameters.pseudoElement].index) {
        parameters.element.pseudoElements.styleSheet.deleteRule(parameters.element.pseudoElements[parameters.pseudoElement].index);
      };

      if (typeof parameters.argument === 'object') {
        parameters.argument = (function() {
          var cloneObject = typeof parameters.argument.pop === 'function' ? [] : {};

          for (var property in parameters.argument) {
            cloneObject[property] = parameters.argument[property];
          };

          return cloneObject;
        })();

        if (!parameters.element.pseudoElements[parameters.pseudoElement].properties && !parameters.element.pseudoElements[parameters.pseudoElement].index) {
          var newIndex = parameters.element.pseudoElements.styleSheet.rules.length || parameters.element.pseudoElements.styleSheet.cssRules.length || parameters.element.pseudoElements.styleSheet.length;

          parameters.element.pseudoElements[parameters.pseudoElement].index = newIndex;
          parameters.element.pseudoElements[parameters.pseudoElement].properties = parameters.argument;
        };

        var properties = '';

        for (var property in parameters.argument) {
          if (typeof parameters.argument[property] === 'function')
            parameters.element.pseudoElements[parameters.pseudoElement].properties[property] = parameters.argument[property]();
          else
            parameters.element.pseudoElements[parameters.pseudoElement].properties[property] = parameters.argument[property];
        };

        for (var property in parameters.element.pseudoElements[parameters.pseudoElement].properties) {
          properties += property + ': ' + parameters.element.pseudoElements[parameters.pseudoElement].properties[property] + ' !important; ';
        };

        parameters.element.pseudoElements.styleSheet.addRule(selector, properties, parameters.element.pseudoElements[parameters.pseudoElement].index);
      } else if (parameters.argument !== undefined && parameters.property !== undefined) {
        if (!parameters.element.pseudoElements[parameters.pseudoElement].properties && !parameters.element.pseudoElements[parameters.pseudoElement].index) {
          var newIndex = parameters.element.pseudoElements.styleSheet.rules.length || parameters.element.pseudoElements.styleSheet.cssRules.length || parameters.element.pseudoElements.styleSheet.length;

          parameters.element.pseudoElements[parameters.pseudoElement].index = newIndex;
          parameters.element.pseudoElements[parameters.pseudoElement].properties = {};
        };

        if (typeof parameters.property === 'function')
          parameters.element.pseudoElements[parameters.pseudoElement].properties[parameters.argument] = parameters.property();
        else
          parameters.element.pseudoElements[parameters.pseudoElement].properties[parameters.argument] = parameters.property;

        var properties = '';

        for (var property in parameters.element.pseudoElements[parameters.pseudoElement].properties) {
          properties += property + ': ' + parameters.element.pseudoElements[parameters.pseudoElement].properties[property] + ' !important; ';
        };

        parameters.element.pseudoElements.styleSheet.addRule(selector, properties, parameters.element.pseudoElements[parameters.pseudoElement].index);
      };
    } else if (parameters.argument !== undefined && parameters.property === undefined) {
      var windowStyle = window.getComputedStyle(
        parameters.element, '::' + parameters.pseudoElement
      ).getPropertyValue(parameters.argument);

      if (parameters.element.pseudoElements) {
        return parameters.element.pseudoElements[parameters.pseudoElement].properties[parameters.argument] || windowStyle;
      } else {
        return windowStyle || null;
      };
    } else {
      console.error('Invalid values!');
      return false;
    };
  };

  Object.defineProperty(Element.prototype, 'styleBefore', {
    enumerable: false,
    value: function(argument, property) {
      return setPseudoElement({
        element: this,
        pseudoElement: 'before',
        argument: argument,
        property: property
      });
    }
  });
  Object.defineProperty(Element.prototype, 'styleAfter', {
    enumerable: false,
    value: function(argument, property) {
      return setPseudoElement({
        element: this,
        pseudoElement: 'after',
        argument: argument,
        property: property
      });
    }
  });
})();

document.querySelector('.element').styleBefore('content', '"New before!"');
.element {
  width: 480px;
  margin: 0 auto;
  border: 2px solid red;
}

.element::before {
  content: 'Old before!';
}
<div class="element"></div>


GitHub: https://github.com/yuri-spivak/managing-the-properties-of-pseudo-elements/

@Tariq Javed 2017-06-28 11:42:19

 $('.span').attr('data-txt', 'foo');
        $('.span').click(function () {
         $(this).attr('data-txt',"any other text");
        })
.span{
}
.span:after{ 
  content: attr(data-txt);
 }
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<div class='span'></div>

@Learner 2016-11-14 13:25:10

There are many answers here but no answer helps to manipulate the css of :before or :after , not even the accepted one.

Here is how I propose to do it. Lets suppose your HTML is like this:

<div id="something">Test</div>

And then you are setting its :before in CSS and designing it like:

#something:before{
   content:"1st";
   font-size:20px;
   color:red;
}
#something{
  content:'1st';
}

Please notice I also set content attribute in element itself so that you can take it out easily later. Now there is a button clicking on which, you want to change the color of :before to green and its font-size to 30px. You can achieve that as follows:

Define a css with your required style on some class .activeS :

.activeS:before{
   color:green !important;
   font-size:30px !important;
 }

Now you can change :before style by adding the class to your :before element as follows:

<button id="changeBefore">Change</button>
<script>
    $('#changeBefore').click(function(){
        $('#something').addClass('activeS');
    });
</script>

If you just want to get content of :before, it can be done as:

<button id="getContent">Get Content</button>
<script>
    $('#getContent').click(function(){
        console.log($('#something').css('content'));//will print '1st'
    });
</script>

Ultimately if you want to dynamically change :before content by jQuery, You can achieve that as follows:

<button id="changeBefore">Change</button>
<script>
    var newValue = '22';//coming from somewhere
    var add = '<style>#something:before{content:"'+newValue+'"!important;}</style>';
    $('#changeBefore').click(function(){
        $('body').append(add);
    });
</script>

Clicking on above "changeBefore" button will change :before content of #something into '22' which is a dynamic value.

I hope it helps

@Gaurav Aggarwal 2016-08-09 06:10:58

Why adding classes or attributes when you can just append a style to head

$('head').append('<style>.span:after{ content:'changed content' }</style>')

@Nick Kline 2011-04-20 17:59:04

You could also pass the content to the pseudo element with a data attribute and then use jQuery to manipulate that:

In HTML:

<span>foo</span>

In jQuery:

$('span').hover(function(){
    $(this).attr('data-content','bar');
});

In CSS:

span:after {
    content: attr(data-content) ' any other text you may want';
}

If you want to prevent the 'other text' from showing up, you could combine this with seucolega's solution like this:

In HTML:

<span>foo</span>

In jQuery:

$('span').hover(function(){
    $(this).addClass('change').attr('data-content','bar');
});

In CSS:

span.change:after {
    content: attr(data-content) ' any other text you may want';
}

@Kevin Peno 2011-08-19 19:28:44

Do you have a link in the spec for using that attr function against the content property? I'm surprised I've never heard of this...

@Kevin Peno 2011-08-19 20:05:28

@Maksim Vi. 2012-01-20 01:05:52

+1 for attr(), too bad i wasn't able to use it with other properties than content. Demo

@BoltClock 2012-02-08 15:49:35

That's because no browser in existence has implemented attr() beyond CSS2 yet, whereas in CSS2 itself attr() has only been defined for the content property.

@chovy 2012-10-10 00:12:42

This does not work for image urls like background-image: url( attr(data-image, url) );

@BoltClock 2013-01-21 10:01:08

@chovy: See my comment for the reason why.

@Jk_ 2013-01-27 17:12:54

How could I use this to pass an img url ? : .attr("data-content",url('../images/loader.gif'));

@user166560 2013-03-23 15:57:23

Updated link for Attribute References: w3.org/TR/css3-values/#attr-notation

@ProblemsOfSumit 2013-06-11 21:09:39

hmm this won't work if you want to change other properties of the pseudo element such as margin via a jQuery animation.

@Blazemonger 2014-02-03 17:35:49

@chofy @Sumit That's true; you can currently only use attr() in CSS to read simple strings for the content property.

@Hanna 2014-04-14 22:51:26

Does anyone know the browser compatibility for this? I assume this won't work for certain versions of IE.

@Blazemonger 2015-06-17 13:34:37

@João Pimentel Ferreira 2018-10-29 20:52:15

Do you need to hover the element to take effect???

@Blazemonger 2014-02-11 18:14:29

You'd think this would be a simple question to answer, with everything else that jQuery can do. Unfortunately, the problem comes down to a technical issue: css :after and :before rules aren't part of the DOM, and therefore can't be altered using jQuery's DOM methods.

There are ways to manipulate these elements using JavaScript and/or CSS workarounds; which one you use depends on your exact requirements.


I'm going to start with what's widely considered the "best" approach:

1) Add/remove a predetermined class

In this approach, you've already created a class in your CSS with a different :after or :before style. Place this "new" class later in your stylesheet to make sure it overrides:

p:before {
    content: "foo";
}
p.special:before {
    content: "bar";
}

Then you can easily add or remove this class using jQuery (or vanilla JavaScript):

$('p').on('click', function() {
    $(this).toggleClass('special');
});

    $('p').on('click', function() {
      $(this).toggleClass('special');
    });
p:before {
  content: "foo";
  color: red;
  cursor: pointer;
}
p.special:before {
  content: "bar";
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>

<p>This is a paragraph.</p>
<p>This is another paragraph.</p>

  • Pros: Easy to implement with jQuery; quickly alters multiple styles at once; enforces separation of concerns (isolating your CSS and JS from your HTML)
  • Cons: CSS must be pre-written, so the content of :before or :after isn't completely dynamic

2) Add new styles directly to the document's stylesheet

It's possible to use JavaScript to add styles directly to the document stylesheet, including :after and :before styles. jQuery doesn't provide a convenient shortcut, but fortunately the JS isn't that complicated:

var str = "bar";
document.styleSheets[0].addRule('p.special:before','content: "'+str+'";');

var str = "bar";
document.styleSheets[0].addRule('p.special:before', 'content: "' + str + '";');
p:before {
  content: "foo";
  color: red;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>

<p class="special">This is a paragraph</p>
<p>This is another paragraph</p>

.addRule() and the related .insertRule() methods are fairly well-supported today.

As a variation, you can also use jQuery to add an entirely new stylesheet to the document, but the necessary code isn't any cleaner:

var str = "bar";
$('<style>p.special:before{content:"'+str+'"}</style>').appendTo('head');

var str = "bar";
$('<style>p.special:before{content:"' + str + '"}</style>').appendTo('head');
p:before {
  content: "foo";
  color: red;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>

<p class="special">This is a paragraph</p>
<p>This is another paragraph</p>

If we're talking about "manipulating" the values, not just adding to them, we can also read the existing :after or :before styles using a different approach:

var str = window.getComputedStyle(document.querySelector('p'), ':before') 
           .getPropertyValue('content');

var str = window.getComputedStyle($('p')[0], ':before').getPropertyValue('content');
console.log(str);

document.styleSheets[0].addRule('p.special:before', 'content: "' + str+str + '";');
p:before {
    content:"foo";
    color: red;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>

<p class="special">This is a paragraph</p>
<p>This is another paragraph</p>

We can replace document.querySelector('p') with $('p')[0] when using jQuery, for slightly shorter code.

  • Pros: any string can be dynamically inserted into the style
  • Cons: original styles aren't altered, just overridden; repeated (ab)use can make the DOM grow arbitrarily large

3) Alter a different DOM attribute

You can also to use attr() in your CSS to read a particular DOM attribute. (If a browser supports :before, it supports attr() as well.) By combining this with content: in some carefully-prepared CSS, we can change the content (but not other properties, like margin or color) of :before and :after dynamically:

p:before {
    content: attr(data-before);
    color: red;
    cursor: pointer;
}

JS:

$('p').on('click', function () {
    $(this).attr('data-before','bar');
});

$('p').on('click', function () {
    $(this).attr('data-before','bar');
});
p:before {
    content: attr(data-before);
    color: red;
    cursor: pointer;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>

<p>This is a paragraph.</p>
<p>This is another paragraph.</p>

This can be combined with the second technique if the CSS can't be prepared ahead of time:

var str = "bar";

document.styleSheets[0].addRule('p:before', 'content: attr(data-before);');

$('p').on('click', function () {
    $(this).attr('data-before', str);
});

var str = "bar";
document.styleSheets[0].addRule('p:before', 'content: attr(data-before) !important;');

$('p').on('click', function() {
  $(this).attr('data-before', str);
});
p:before {
  content: "foo";
  color: red;
  cursor: pointer;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>

<p>This is a paragraph.</p>
<p>This is another paragraph.</p>

  • Pros: Doesn't create endless extra styles
  • Cons: attr in CSS can only apply to content strings, not URLs or RGB colors

@user2101068 2015-06-19 17:05:37

I'm trying to dynamically set glyphicon values (i.e., via their hex values) in ::after psedo. content: element (e.g., content: "\e043";). it doesn't seem to work for me so I'm assuming it doesn't work for hex values for glyphicons either?

@Blazemonger 2015-06-19 17:41:59

@user2101068 You should post that as a new question. I'd have to see all the code you're using.

@user2101068 2015-06-19 18:20:18

Blazemonger, thanks for the quick reply..unfortunately there is a quite a bit of code and it would take quite a bit of effort to snip out the relevant code. I've already spent 12+ hours trying to get this work and this was my last gasp effort to get it to work. I need to cut my losses. I was hoping you might be able to just verify my assumption re: hex values when using the technique you described in #3 above (before code snippet). I can insert hex string in content element but it displays text for glyphicon hex value rather than the actual glyphicon. Impression without seeing all code?

@Blazemonger 2015-06-19 19:06:51

@user2101068 Don't use the hex string; instead, copy and paste the actual Unicode character into the HTML attribute. jsfiddle.net/mblase75/Lcsjkc5y

@Picard 2016-09-02 10:58:47

regarding solution 2. & 3. actually you can prevent stylesheet from (over)growing if you use: document.styleSheets[0].insertRule(rule, index), then using this index you can remove the rules when not needed: document.styleSheets[0].deleteRule(index)

@Adarsh Hegde 2015-04-20 11:59:54

This is not practical as i did not write this for real world uses, just to give you a example of what can be achieved.

css = {
before: function(elem,attr){ 

if($("#cust_style") !== undefined){ 
$("body").append("<style> " + elem + ":before {"  + attr +  "} </style>"); 
} else {
 $("#cust_style").remove();
$("body").append("<style> " + elem + ":before {"  + attr +  "} </style>"); 
}

}, after: function(elem,attr){
if($("#cust_style") !== undefined){ 
$("body").append("<style> " + elem + ":after {"  + attr +  "} </style>"); 

} else { $("#cust_style").remove();
$("body").append("<style> " + elem + ":after {"  + attr +  "} </style>"); 
}
}
}

this currently add's a / or appends a Style element which contains your necessary attribute's which will take affect on the target element's after Pseudo element.

this can be used as

css.after("someElement"," content: 'Test'; position: 'absolute'; ") // editing / adding styles to :after

and

css.before( ... ); // to affect the before pseudo element.

as after: and before: pseudo elements are not directly accessible through DOM it is currently not possible to edit the Specific values of the css freely.

my way was just a example and its not good for practice, you can modify it try some of your own tricks and make it correct for real world usage.

so do your own experimentation's with this and others!

regards - Adarsh Hegde.

@Gustavo Sousa 2011-03-17 06:46:46

You can't select pseudo elements in jQuery because they are not part of DOM. But you can add an specific class to the father element and control its pseudo elements in CSS.

EXAMPLE

In jQuery:

<script type="text/javascript">
    $('span').addClass('change');
</script>

In CSS:

span.change:after { content: 'bar' }

@Alexander Shutau 2014-10-13 13:45:45

You may create a fake property or use an existing one and inherit it in the pseudo-element's stylesheet.

var switched = false;

// Enable color switching
setInterval(function () {
    var color = switched ? 'red' : 'darkred';
    var element = document.getElementById('arrow');
    element.style.backgroundColor = color;
    
    // Managing pseudo-element's css
    // using inheritance.
    element.style.borderLeftColor = color;
    
    switched = !switched;
}, 1000);
.arrow {
    /* SET FICTIONAL PROPERTY */
    border-left-color:red;
    
    background-color:red;
    width:1em;
    height:1em;
    display:inline-block;
    position:relative;
}
.arrow:after {
    border-top:1em solid transparent;
    border-right:1em solid transparent;
    border-bottom:1em solid transparent;
    border-left:1em solid transparent;
    
    /* INHERIT PROPERTY */
    border-left-color:inherit;
    
    content:"";
    width:0;
    height:0;
    position:absolute;
    left:100%;
    top:-50%;
}
<span id="arrow" class="arrow"></span>

It seems it doesn't work for "content" property :(

@Nedudi 2014-07-15 21:55:01

Here is the way to access :after and :before style properties, defined in css:

// Get the color value of .element:before
var color = window.getComputedStyle(
    document.querySelector('.element'), ':before'
).getPropertyValue('color');

// Get the content value of .element:before
var content = window.getComputedStyle(
    document.querySelector('.element'), ':before'
).getPropertyValue('content');

@KingRider 2016-12-29 15:14:47

Impossible make setProperty? i try not work.

@aimiliano 2014-07-10 15:26:38

Thank you all! i managed to do what i wanted :D http://jsfiddle.net/Tfc9j/42/ here take a look

i wanted to have the opacity of an outer div to be different from the opacity of the internal div and that change with a click somwewhere ;) Thanks!

   $('#ena').on('click', function () {
        $('head').append("<style>#ena:before { opacity:0.3; }</style>");
    });

$('#duop').on('click', function (e) {

        $('head').append("<style>#ena:before { opacity:0.8; }</style>");

     e.stopPropagation(); 
    });

#ena{
    width:300px;
    height:300px;
    border:1px black solid;
    position:relative;
}
#duo{
    opacity:1;
    position:absolute;
    top:50px;
  width:300px;
    height:100px;
      background-color:white;
}
#ena:before {
    content: attr(data-before);
    color: white;
    cursor: pointer;
    position: absolute;
    background-color:red;
    opacity:0.9;
    width:100%;
    height:100%;
}


<div id="ena">
    <div id="duo">
        <p>ena p</p>
        <p id="duop">duoyyyyyyyyyyyyyy p</p>

    </div>   


</div>

@KingRider 2016-12-29 15:15:43

Not try append, use html is best prevent

@scott 2017-01-18 18:02:45

+1. This is exactly what I was searching for, to change the opacity of a div. The other answers are very thorough, but they all focused on adding styles, not modifying existing ones. Thank you!

@pupitetris 2017-10-27 15:22:04

Watch out: here you are appending a style tag to the head every time one of those clicks is handled. I'd code a way to remove the old one before adding a new one.

@user595349 2014-06-14 20:13:28

IF you want to to manipulate the ::before or ::after sudo elements entirely through CSS, you could do it JS. See below;

jQuery('head').append('<style id="mystyle" type="text/css"> /* your styles here */ </style>');

Notice how the <style> element has an ID, which you can use to remove it and append to it again if your style changes dynamically.

This way, your element is style exactly how you want it through CSS, with the help of JS.

@ekkis 2014-09-28 00:41:59

this is very cool for another reason: if one's building a jquery plugin and doesn't want to require the inclusion of a stylesheet but needs to predefine certain styles, this is a great way to do it!

@Coyote 2014-03-18 23:27:20

Here is the HTML:

<div class="icon">
  <span class="play">
    ::before
  </span>
</div>

Computed style on 'before' was content: "VERIFY TO WATCH";

Here is my two lines of jQuery, which use the idea of adding an extra class to specifically reference this element and then appending a style tag (with an !important tag) to changes the CSS of the sudo-element's content value:

$("span.play:eq(0)").addClass('G');

$('body').append("<style>.G:before{content:'NewText' !important}</style>");

@Ivan Chaer 2012-10-18 10:20:22

In the line of what Christian suggests, you could also do:

$('head').append("<style>.span::after{ content:'bar' }</style>");

@pmrotule 2015-06-11 15:22:36

That's a really nice solution to change the style as well!

@K.S. 2016-09-20 13:00:09

Here should be added an id-attribute, so the element can be selected and deleted before a new one is added. If not, there can come up a lot of unnecessary style-nodes.

@Christian 2012-09-12 13:27:47

one working but not very efficient way is to add a rule to the document with the new content and reference it with a class. depending on what is needed the class might need an unique id for each value in content.

$("<style type='text/css'>span.id-after:after{content:bar;}</style>").appendTo($("head"));
$('span').addClass('id-after');

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