First JavaScript program code

<! DOCTYPE html>
The browser appears as follows:

Note that the JavaScript code is written here:

<script type="text/javascript">Indicates that the text type is between <script></script>, JavaScript is meant to tell the browser that the text is in the JavaScript language.
Can javascript code be written only in HTML files? Of course not, we can separate the HTML file and JS code, and create a separate JavaScript file (JS file), its file suffix is usually. js, and then the JS code directly in the JS file.
Note: In the JS file, you do not need to <script> tags, directly write JavaScript code on it.
JS file can not be run directly, embedded in the HTML file to execute, we need to add the following code in HTML, the JS file can be embedded in the HTML file.



First JavaScript program code