One major cause of slow web pages is the so-called blocking script. A blocking script is a JavaScript file whose loading and execution blocks the loading of a web page. In extreme circumstances, a browser may download an entire webpage and show a blank screen for several seconds or longer while the JavaScript is loaded and parsed. Because web users tend to become bored quickly, this situation should absolutely be avoided.
Fortunately, there are several ways to defer JavaScript loading and execution and to make your web pages display faster.
The first way is by using the defer attribute of the script element. Here’s what it looks like:
<script src="myscript.js" defer></script>
Note that the defer attribute can be used only with external JavaScript files. It can’t be applied to