Dr.Cooper 0 Newbie Poster

I am trying to develop and application that takes a webpage and changes the value attribute of an input type. For example load a webpage with
view sourceprint?

<input type="text" size="20" name="UserName" value=""/>

and changes it to

<input type="text" size="20" name="UserName" value="User3"/>

using system.net.webclient.
Also, I want to know how to execute javascript code on-the-fly. A command like:

document.frmLogin.submit()

Thanks.