CSS Up Top, JavaScript at the Bottom

CSS Goes In The <head>

Styles need to be loaded first before the page is displayed. Otherwise there will be a flash and elements on the page will shift creating a bad experience.

JavaScript Belongs At The End of the Document

JavaScript can't do anything until the page loads anyway and <script> tags block parallel downloading, resulting in longer page load times.

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
"http://www.w3.org/TR/html4/strict.dtd">
<html>
<head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>CSS Up Top, JavaScript at the Bottom - Frontend Development Tips & Tricks by Russell Heimlich</title> <link href="css/reset.css" rel="stylesheet" media="all"> <link href="css/main.css" rel="stylesheet" media="all"> </head> <body> … <script type="text/javascript" src="js/jquery.js"></script> </body> </html>

Source: Best Practices for Speeding Up Your Web Site - Yahoo!