run js on html tag code example

Example 1: linking a script .js

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

Example 2: hello world javascript

// Output Hello World! in the console.
console.log("Hello World!");

Example 3: how to enter javascript in html

<script type="text/javascript">
  alert("This alert box was called with the onload event");
</script>