parent.rightFrame.document.theForm.TextBox1.value = "7";
which simulates a user typing 7 into the first text box. The idea of this testing technique is simple in principle but the details are somewhat tricky. In particular, synchronizing the actions on the Web app is rather delicate. Explaining exactly how this Web testing technique works was one of the main motivators for me to write ".NET Test Automation Recipes" and I dedicate a chapter to all the details.