$(document).ready(function(){
//demonstrates the add class
$("button").click(function(){
$("h1,h2,p").addClass("blue");
$("div").addClass("important");
});
//demonstrate the remove class
$("#remove").click(function(){
$("h1,h2,p").removeClass("blue");
});
});
<h1>Heading 1</h1>
<h2>Heading 2</h2>
<p>This is a paragraph.</p>
<p>This is another paragraph.</p>
<div>This is some important text!</div>
<br>
<button>Add classes to elements</button>
<button id="remove">remove classes to elements</button>
.blue
{
color:blue;
}
.important{
color:red;
}