jQuery: Using jQuery add a new class to an element that already has a class

Last update on August 19 2022 21:50:45 (UTC/GMT +8 hours)

jQuery Fundamental - I : Exercise-7

Using jQuery add a new class to an element that already has a class.

Add the "w3r_bg_blue" class to a paragraph that already has a "w3r_bg_orange" class

 <p class="w3r_bg_orange">The best way we learn anything is by practice and exercise questions.</p>

p {
    background: white;
  }
  .w3r_bg_orange{
    background: orange;
  }
  .w3r_bg_red {
    color: red;
  }

Sample solution :

HTML Code :

<!DOCTYPE html>
<html>
<head>
<script src="https://code.jquery.com/jquery-git.js"></script>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width">
<title>JS Bin</title>
</head>
<body>
<p class="w3r_bg_orange">The best way we learn anything is by practice and exercise questions.</p>
<button id="button1">Click to see the effect</button>
</body>
</html>

CSS Code:

button {
    display: block;
    margin: 20px 0 0 0;
    } 
 
p {
    background: white;
  }
  .w3r_bg_orange{
    background: orange;
  }
  .w3r_bg_red {
    color: red;
  }

JavaScript Code :

$('#button1').click(function(){ 
$( "p" ).addClass(function( index, currentClass ) {
  var addedClass;
   if ( currentClass === "w3r_bg_orange" ) {
    addedClass = "w3r_bg_red";
    }
 return addedClass;
});
});

Used Methods :

.addClass() : Adds the specified class(es) to each element in the set of matched elements

See the Pen jquery-fundamental-exercise-7 by w3resource (@w3resource) on CodePen.

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