How to use external “.js” files in an HTML file?

Create external JavaScript file with the extension .js. After creating, add it to the HTML file in the script tag. The src attribute is used to include that external JavaScript file.

If you have more than one external JavaScript file, then add it in the same web page to increase performance of the page.

Let’s say the following new.js is our external JavaScript file −

function display() {
   alert("Hello World!");

Now add the external JavaScript file to the HTML web page −

      <input type="button" value="Result" onclick="display()"/>
      <script src="new.js">