Entire Code.

<html>
<head>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<form>
<input type="text" id="textfield" />
</form>
<script type="text/css">
.fade-out {
	transition: color 3s ease-in-out;
	color: rgba(255,255,255,0); //transparent black
}
</script>
<script type="text/javascript>
window.onload = function(){
	var textfieldTimer;

	$("#textfield").keyup( function(){
		clearTimeout(textfieldTimer);
		var field = $(this);
		textfieldTimer = setTimeout(function(){
			field.addClass('fade-out');
			textfieldTimer = setTimeout(function(){
				field.val('');
				console.log(field);
			}, 3000
			);
		}, 5000);
	});

	$("#textfield").keydown(function(){
		clearTimeout(textfieldTimer);
		$(this).removeClass('fade-out');

	});
};
</script>

</head>
</html>