From Forum Nokia Wiki

JavaScript is, one of the most used, scripting language which are utilized on the web development. It's also well known client side scripting language, but can also be used on the server side scripting.

JavaScript can be used example to, detect incoming browser, validate forms data, make mathematical calculations, react the user activities on the page.

JavaScript can added directly into HTML pages

<script type="text/javascript">
		….code….
	</script>

or can be created the link to the external file

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

End user has possibility to choose on the browser settings that is the scripting functionality supported.