Enabling IntelliSense for Client Object Model script in Visual Studio

Message
A simple way to enable/activate IntelliSense in Visual Studio while writing ECMA script. It allows, for example,  to write your javascript or jQuery code for SharePoint saving you a lot of time.
Some references: http://msdn.microsoft.com/en-us/library/ff798328.aspx

Context
Visual Studio 2010, SharePoint 2010, Visual WebPart

Explanation

Following is the list of debug .js files present in _layouts folder and depending upon the objects you are working with, you may need to add a reference to any of them to get IntelliSense.

• SP.debug.js (to get IntelliSense on list objects)
• SP.Core.debug.js
• SP.Ribbon.debug.js
• SP.Runtime.debug.js
• JsGrid.debug.js
• JsGrid.Gantt.debug.js

Solution
Add following lines at the start of the .ascx file in a visual webpart.

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

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

<script type="text/javascript" src="/_layouts/SP.Core.debug.js">

PS: Exclude these references while deploying the code to production environment.