jQuery offers various methods, like addClass(), removeClass(), toggleClass(), and more to change the CSS classes assigned to HTML elements.
addClass() MethodThe jQuery addClass() method adds one or more classes to the selected elements.
In the example below, clicking the button will add the class .page-header to the <h1> and the class .highlight to the <p> elements with the class .hint.
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>jQuery addClass() Demo</title>
<style>
.page-header{
color: red;
text-transform: uppercase;
}
.highlight{
background: yellow;
}
</style>
<script src="https://code.jquery.com/jquery-3.5.1.min.js"></script>
<script>
$(document).ready(function(){
$("button").click(function(){
$("h1").addClass("page-header");
$("p.hint").addClass("highlight");
});
});
</script>
</head>
<body>
<h1>Demo Text</h1>
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit...</p>
<p class="hint"><strong>Tip:</strong> Lorem Ipsum is dummy text.</p>
<button type="button">Add Class</button>
</body>
</html>You can also add multiple classes to the elements at once. Simply provide a space-separated list of classes within the addClass() method, like this:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>jQuery addClass() Demo</title>
<style>
.page-header{
color: red;
text-transform: uppercase;
}
.highlight{
background: yellow;
}
</style>
<script src="https://code.jquery.com/jquery-3.5.1.min.js"></script>
<script>
$(document).ready(function(){
$("button").click(function(){
$("h1").addClass("page-header highlight");
});
});
</script>
</head>
<body>
<h1>Hello World</h1>
<p>The quick brown fox jumps over the lazy dog.</p>
<button type="button">Add Class</button>
</body>
</html>removeClass() MethodSimilarly, you can remove classes from elements using the jQuery removeClass() method. This method can remove a single class, multiple classes, or all classes at once from the selected elements.
In the example below, clicking the button will remove the class .page-header from the <h1> element, and the classes .hint and .highlight from <p> elements.
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>jQuery removeClass() Demo</title>
<style>
.page-header{
color: red;
text-transform: uppercase;
}
.highlight{
background: yellow;
}
</style>
<script src="https://code.jquery.com/jquery-3.5.1.min.js"></script>
<script>
$(document).ready(function(){
$("button").click(function(){
$("h1").removeClass("page-header");
$("p").removeClass("hint highlight");
});
});
</script>
</head>
<body>
<h1 class="page-header">Demo Text</h1>
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit...</p>
<p class="hint highlight"><strong>Tip:</strong> Lorem Ipsum is dummy text.</p>
<button type="button">Remove Class</button>
</body>
</html>When the removeClass() method is called without an argument, it removes all classes from the selected elements. Here's an example:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>jQuery removeClass() Demo</title>
<style>
.page-header{
color: red;
text-transform: uppercase;
}
.highlight{
background: yellow;
}
</style>
<script src="https://code.jquery.com/jquery-3.5.1.min.js"></script>
<script>
$(document).ready(function(){
$("button").click(function(){
$("h1").removeClass();
$("p").removeClass();
});
});
</script>
</head>
<body>
<h1 class="page-header">Demo Text</h1>
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit...</p>
<p class="hint highlight"><strong>Tip:</strong> Lorem Ipsum is dummy text.</p>
<button type="button">Remove Class</button>
</body>
</html>toggleClass() MethodThe jQuery toggleClass() method adds or removes one or more classes from the selected elements. If the selected element already has the class, it will be removed; if the element does not have the class, it will be added—effectively toggling the classes.
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>jQuery toggleClass() Demo</title>
<style>
p{
padding: 10px;
cursor: pointer;
font: bold 16px sans-serif;
}
.highlight{
background: yellow;
}
</style>
<script src="https://code.jquery.com/jquery-3.5.1.min.js"></script>
<script>
$(document).ready(function(){
$("p").click(function(){
$(this).toggleClass("highlight");
});
});
</script>
</head>
<body>
<p>Click on me to toggle highlighting.</p>
<p class="highlight">Click on me to toggle highlighting.</p>
<p>Click on me to toggle highlighting.</p>
</body>
</html>You will learn about manipulating CSS properties in the next chapter »