<!DOCTYPE html>
<html>
<head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.2/jquery.min.js"></script>
<script>
$(document).ready(function(){
$("#p1").mouseenter(function(){
alert("You entered p1!");
});
});
</script>
</head>
<body>
<p id="p1">Enter this paragraph.</p>
</body>
</html>