How to call external JavaScript function in HTML

In Layman terms, you need to include external js file in your HTML file & thereafter you could directly call your JS method written in an external js file from HTML page. Follow the code snippet for insight:-

caller.html

<script type="text/javascript" src="external.js"></script>
<input type="button" onclick="letMeCallYou()" value="run external javascript">

external.js

function letMeCallYou()
{
    alert("Bazinga!!!  you called letMeCallYou")
}

Result :

If a <script> has a src then the text content of the element will be not be executed as JS (although it will appear in the DOM).

You need to use multiple script elements.

1. a <script> to load the external script

2. a <script> to hold your inline code (with the call to the function in the external script)

   scroll_messages();