demo.html

<!DOCTYPE html>
<html>
<head>
	<title>Placeholdr Demo</title>
	<script src="//ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js"></script>
	<script type="text/javascript" src="placeholdr.min.js"></script>
</head>
<body>
	<form>
		<input type="text" name="username" id="username" placeholder="Username" />
		<input type="password" name="password" id="password" placeholder="Password" />
		<textarea name="comment" id="comment" placeholder="Comment Here"></textarea>
		<input type="submit" />
	</form>
	<button id="values">Display Values</button>
</body>

<script type="text/javascript">
$("#values").click(function(){
	alert("Username Value: " + $("#username").val());
	alert("Password Value: " + $("#password").val());
	alert("Comment Value: " + $("#comment").val());
});
</script>

</html>