jQuery toggleClass()
control class adding and deleting
<!DOCTYPE html> <html> <head> <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js"> </script>//from w w w .ja va2 s . c o m <script> $(document).ready(function(){ $("#add").click(function(){ $("p").toggleClass("main",true); }); $("#remove").click(function(){ $("p").toggleClass("main",false); }); }); </script> <style> .main { font-size: 120%; color: red; } </style> </head> <body> <p>This is a paragraph.</p> <p class="main">This is another paragraph.</p> <button id="add">Add class "main"</button> <button id="remove">Remove class "main"</button> </body> </html>