I have an [url removed, login to view] 4.0 webform (uses no AJAX) where users fill in some information, in five steps (a wizard).
During step 2 (see attached screenshot) and step 4, when they give an e-mail address, the address will be checked when they click “next”. The application will lookup mx-records and contact the mailserver. This can be time consuming, mostly a few seconds but sometimes 10 seconds.
Attached is a zipped folder with a little testsite, containing the .aspx page and the codebehind (written in VB). The codeblock where the mailadress is checked, is replaced with a wait statement of 2,5 seconds for testing purposes.
If the project is assigned to you and you have adapted the files of the testsite, put the working example online so I can test it.