if ($( "#foo" ).hasClass('className')) {
$( "#foo" ).removeClass( 'className');
} else {
$( "#foo" ).addClass( 'className');
}$('some_element').addClass('some-class');
// You can add more than one class at one time
$('some_element').addClass('some-class another-class yet-another-class');
// Even thought jQuery allows you to do this
$('some_element').addClass('some-class').addClass('another-class').addClass('yet-another-class');
// That would be really wasteful, think of the planet!
// But more importantly, your RAM
// oh and those poor folks who be viewing your website$("#elem").addClass("classname");$( "p" ).addClass( "selected highlight" );$( "p" ).removeClass( "myClass noClass" ).addClass( "yourClass" );
$("#my_id").attr("class", "my_new_class_name");$( "p" ).addClass( "myClass yourClass" );
//On button cick
<script>
$(document).ready(function(){
$("button").click(function(){
$("p:first").addClass("intro");
});
});
</script>
//On page load
<script>
$(document).ready(function(){
if ($( "#element" ).hasClass('className')) {
$( "#element" ).removeClass( 'className');
} else {
$( "#element" ).addClass( 'className');
}
});
</script>$('body').addClass(newClass);
jQuery( "button.hamburger" ).click(function() {
jQuery(this).addClass( "is-active" );
});1
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<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>addClass demo</title>
<link rel="stylesheet" href="//code.jquery.com/ui/1.12.1/themes/smoothness/jquery-ui.css">
<style>
div {
width: 100px;
height: 100px;
background-color: #ccc;
}
.big-blue {
width: 200px;
height: 200px;
background-color: #00f;
}
</style>
<script src="//code.jquery.com/jquery-1.12.4.js"></script>
<script src="//code.jquery.com/ui/1.12.1/jquery-ui.js"></script>
</head>
<body>
<div></div>
<script>
$( "div" ).click(function() {
$( this ).addClass( "big-blue", 1000, "easeOutBounce" );
});
</script>
</body>
</html>$('#element').addClass('active');