How to run Document Object Model JavaScript
<!DOCTYPE html>
<script>
alert("Step 1: put your JavaScript in HTML <script> tags");
//-----------------------------------------------------------
alert("Step 2: save your file as .html, e.g. myscript.html");
//-----------------------------------------------------------
alert("Step 3: open your .html file in your browser");
//-----------------------------------------------------------
alert("Note: Don't forget to close your HTML /script tag:")
</script>
put js in <script> tags and save as html.
launch html file in browser.
BOM = Browser Object Model.