A &lt;script&gt; tag will block DOM tree construction and rendering in browsers but will not block scanning ahead for things to load (and at least in Firefox won&#x27;t even block tokenization of the HTML).  So if you have a &lt;link rel=&quot;stylesheet&quot;&gt; at the end of &lt;body&gt; it will likely start loading even before the scripts before it have had a chance to load and run.<p>A bigger problem is that in some browsers (not Firefox, but iirc yes Chrome) that stylesheet load will then itself block rendering.