Console function in Java to debug!

<!DOCTYPE html>
<html>
<body>

<h1>My First Web Page</h1>
<p>My first paragraph.</p>

<p>
Activate debugging in your browser (Chrome, IE, Firefox) with F12, and select “Console” in the debugger menu.
</p>

<script>
console.log(5 + 6);
</script>

</body>
</html>

 

If this is to be work well in Firefox,,then Firebug need to be open ,ot it would result in page crash!