We are plannning to use Ajax in our ASP.net project. However, we still want the member panel of our web site to work in all browsers. We have decided not to use Ajax in some forms where browser independence is must. 

I am now confused with whether we should use ASP.NET controls or HTML controls or both? 

I have two questions:

* Are there any problems that I might face using either of approach?
* Also which one is better considering efficiency and performance?