In Order to Use HTML 5 and CSS 3.0 you have to use Visual Studio 2010 with Service Pack 1.
You can download the Service pack 1 from Microsoft Download Center.It is free or if you have windows updates turned on then you can check for updates and see if it is listed in Important or Optional Updates.
Here is the Link to Download :- http://go.microsoft.com/fwlink/?LinkId=210710
This is in ISO Format just extract and install it.
Here are the System Requirements.
Supported Operating Systems: Windows 7, Windows Server 2003 R2 (32-Bit x86), Windows Server 2003 R2 x64 editions, Windows Server 2003 Service Pack 2, Windows Server 2008 R2, Windows Server 2008 Service Pack 2, Windows Vista Service Pack 2, Windows XP Service Pack 3
Windows XP (x86) with Service Pack 3 - all editions except Starter Edition
Windows Vista (x86 & x64) with Service Pack 2 - all editions except Starter Edition
Windows 7 (x86 and x64)
Windows Server 2003 (x86 & x64) with Service Pack 2 - all editions
Users will need to install MSXML6 if not already present
Windows Server 2003 R2 (x86 and x64) - all editions
Windows Server 2008 (x86 and x64) with Service Pack 2 - all editions
Windows Server 2008 R2 (x64) - all editions
64-Bit (x64) (WOW)
1.6GHz or faster processor
1024 MB RAM (1.5 GB if running in a virtual machine)
5.5 GB of available hard-disk space
5400 RPM hard drive
DirectX 9 capable video card running at 1024 x 768 or higher-resolution display
After you download and install the Service Pack 1 you have to change some settings for that open a New Website ==> Add a new Form
Now go to Tools ==> Options ==> Expand the arrow of text editor ==> Go to Html and expand the List of HTML and click on validation ==> You will find HTML5 select it.
Now go the Web Form you have added and try
<video id="video1" runat = "server"></video>
You will get the intellisense automatically and make sure that HTML5 is selected on the topParthibansk, if this helps please login to Mark As Answer. | Alert Moderator