javascript call in external file inside html code example

Example 1: html bind js file

<script type="text/javascript" src="path-to-javascript-file.js"></script>

Example 2: how to include external javascript in html

<script src="script.js">

Example 3: How to add js file to a site through url

var jsFile = document.createElement("script");
jsFile.src = "homePage.js";  // it can be path also  "{themes('/scripts/homePage.js')}"
document.body.appendChild(jsFile);  //append it as src to body

Example 4: javascript class in external file

class User {
    //...
}

module.exports = User