how to implement javascript into html code example

Example 1: how to reference a javascript file in html

<script type="text/javascript" src="path/filename.js"></script>

Example 2: how to use javascript in html

<!-- include an external javascript document -->
<script src="myJavaScript.js" charset="utf-8"></script>

<!-- JavaScript inside html element -->
<script>
  console.log("This is JavaScript");
</script>

Example 3: how to enter javascript in html

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