Tryit Editor v1.8

Source Code:

<!DOCTYPE html>
<html>
<head>
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js">
</script>
<script>
$(document).ready(function(){
  $("button").click(function(){
    alert($("#w3s").attr("href"));
  });
});
</script>
</head>

<body>
<p><a href="http://www.w3schools.com" id="w3s">W3Schools.com</a></p>
<button>Show href Value</button>
</body>
</html>

Result:

W3Schools.com - Try it yourself

Edit the code above and click "Submit Code" to see the result.