<!DOCTYPE html>
<html>
<head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.2/jquery.min.js"></script>
<script>
$(document).ready(function(){
$("button").click(function(){
$("p").remove(".test, .demo");
});
});
</script>
<style>
.test {
color: red;
font-size: 20px;
}
.demo {
color: green;
font-size: 25px;
}
</style>
</head>
<body>
<p>This is a paragraph.</p>
<p class="test">This is p element with class="test".</p>
<p class="test">This is p element with class="test".</p>
<p class="demo">This is p element with class="demo".</p>
<button>Remove all p elements with class="test" and class="demo"</button>
</body>
</html>