::before (:before)

In CSS, ::before creates a pseudo-element that is the first child of the selected element. It is often used to add cosmetic content to an element with the content property. It is inline by default.

Try it

Note: The pseudo-elements generated by ::before and ::after are contained by the element's formatting box, and thus don't apply to replaced elements such as <img>, or to <br> elements.

Syntax

::before

Note: CSS3 introduced the ::before notation (with two colons) to distinguish pseudo-classes from pseudo-elements. Browsers also accept :before, introduced in CSS2.

Examples

Adding quotation marks

One simple example of using ::before pseudo-elements is to provide quotation marks. Here we use both ::before and ::after to insert quotation characters.

HTML

<q>Some quotes</q>, he said, <q>are better than none.</q>

CSS

q::before {
  content: "«";
  color: blue;
}

q::after {
  content: "»";
  color: red;
}

Result

Decorative example

We can style text or images in the content property almost any way we want.

HTML

<span class="ribbon">Notice where the orange box is.</span>

CSS

.ribbon {
  background-color: #5BC8F7;
}

.ribbon::before {
  content: "Look at this orange box.";
  background-color: #FFBA10;
  border-color: black;
  border-style: dotted;
}

Result

To-do list

In this example we will create a simple to-do list using pseudo-elements. This method can often be used to add small touches to the UI and improve user experience.

HTML

<ul>
  <li>Buy milk</li>
  <li>Take the dog for a walk</li>
  <li>Exercise</li>
  <li>Write code</li>
  <li>Play music</li>
  <li>Relax</li>
</ul>

CSS

li {
  list-style-type: none;
  position: relative;
  margin: 2px;
  padding: 0.5em 0.5em 0.5em 2em;
  background: lightgrey;
  font-family: sans-serif;
}

li.done {
  background: #CCFF99;
}

li.done::before {
  content: '';
  position: absolute;
  border-color: #009933;
  border-style: solid;
  border-width: 0 0.3em 0.25em 0;
  height: 1em;
  top: 1.3em;
  left: 0.6em;
  margin-top: -1em;
  transform: rotate(45deg);
  width: 0.5em;
}

JavaScript

const list = document.querySelector('ul');
list.addEventListener('click', (ev) => {
  if (ev.target.tagName === 'LI') {
     ev.target.classList.toggle('done');
  }
}, false);

Here is the above code example running live. Note that there are no icons used, and the check-mark is actually the ::before that has been styled in CSS. Go ahead and get some stuff done.

Result

Special characters

As this is CSS; not HTML, you can not use markup entities in content values. If you need to use a special character, and can not enter it literally into your CSS content string, use a unicode escape sequence, consisting of a backslash followed by the hexadecimal unicode value.

HTML

<ol>
  <li>Crack Eggs into bowl</li>
  <li>Add Milk</li>
  <li>Add Flour</li>
  <li aria-current='step'>Mix thoroughly into a smooth batter</li>
  <li>Pour a ladleful of batter onto a hot, greased, flat frying pan</li>
  <li>Fry until the top of the pancake loses its gloss</li>
  <li>Flip it over and fry for a couple more minutes</li>
  <li>serve with your favorite topping</li>
</ol>

CSS

li {
  padding:0.5em;
}

li[aria-current='step'] {
  font-weight:bold;
}

li[aria-current='step']::after {
  content: " \21E6"; /* Hexadecimal for Unicode Leftwards white arrow*/
  display: inline;
}

Result

Accessibility concerns

Using a ::before pseudo-element to add content is discouraged, as it is not reliably accessible to screen readers.

Specifications

Specification
CSS Pseudo-Elements Module Level 4
# generated-content

Browser compatibility

BCD tables only load in the browser

See also