⚠ī¸ Warning ⚠ī¸ Deprecated Code! This video tutorial contains outdated code.
💡 If you wish to update it, any AI assistant will update the code for you in seconds.

Window Size Responsive CSS Layout Stylesheet Change Tutorial

Published : November 17, 2014   •   Last Edited : November 24, 2025   •   Author : Adam Khoury
Learn to program layout responses to the browser window size changes using JavaScript to affect the CSS style sheet link element in the document. The script also handles layout adjustment when the document is initially loading. 
<!DOCTYPE html>
<html>
<head>
<link id="pagestyle" rel="stylesheet" type="text/css" href="large.css">
<script>
function layoutHandler(){
	var styleLink = document.getElementById("pagestyle");
	if(window.innerWidth < 900){
		styleLink.setAttribute("href", "mobile.css");
	} else if(window.innerWidth < 1200){
		styleLink.setAttribute("href", "medium.css");
	} else {
	    styleLink.setAttribute("href", "large.css");
	}
}
window.onresize = layoutHandler;
layoutHandler();
</script>
</head>
<body>
<div id="my_header"></div>
<div id="my_menu">
  <a href="#">Home</a>
  <a href="#">Services</a>
  <a href="#">Staff</a>
  <a href="#">Contact</a>
</div>
<div id="my_content">
Lorem ipsum goes here as dummy text, lots of it.
</div>
</body>
</html>
▲