How to make internet explorer transparent in ASP.net using C#

The Internet Explorer window itself or an element inside it? Either way, the Internet Explorer cannot be made transparent; and to make elements of the page transparent, you would use CSS.

Thanks for your reply. Anyway I needed to know how to make the browser windows tranparent in ASP.net as we can make the windows forms transparent using the form.Opacity property in C# or VB.net. Could you help me with this?

If you plan on making the user's browser window transparent using code interpreted by the browser itself, that is impossible. You can't do that with ASP.NET, nor with any other web development language. The classes and namespaces available for Windows Forms are not the same as the ones for ASP.NET.