HI Krushna,
I am not sure about the motive behind starting such project from scratch. But it will be kind of re-inventing wheel !
There is one good open source tool "HtmlAgilityPack" on codeplex at
www.htmlagilitypack.codeplex.com[
^]
This also contains source code in case you want to extend the functionality to suit your requirement.
Hope that helps. If it does, mark the answer as solution/upvote.
Thanks
Milind