<!DOCTYPE html>
<html>
<head>
<script src="/lib/jquery-1.12.2.min.js"></script>
<script>
$(document).ready(function(){
$("input").blur(function(){
alert("This input field has lost its focus.");
});
});
</script>
</head>
<body>
Enter your name: <input type="text">
<p>Write something in the input field, and then click outside the field to lose focus (blur).</p>
</body>
</html>