Tryit Editor v2.9

Edit This Code:
<!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(){
        $("input:text").val(function(n, c){
            return c + " Griffin";
        });
    });
});
</script>
</head>
<body>

<p>Name: <input type="text" name="user" value="Peter"></p>

<button>Set the value of the input field</button>

</body>
</html>