<!DOCTYPE html>
<html>
<head>
<style>
.myClass:after {
content: " But you already knew that.";
}
</style>
</head>
<body>
<p>You can not style a pseudo-class on a particular element, but you can get the same result by creating a class in your STYLE section (or stylesheet) and add that class to the specified element.</p>
<p>Click the "Try it" button to add the class "myClass" to the DIV element:</p>
<button onclick="myFunction()">Try it</button>
<div id="myDIV">This is my DIV element.</div>
<script>
function myFunction() {
document.getElementById("myDIV").className += " myClass";
}
</script>
</body>
</html>