You should know how to create a Sharepoint list and how to open the site in Sharepoint designer. Following is a list with Email fields. Let's say we have to validate so that only a valid email can be entered. If not valid then the Error Message appears next to the field Now open the site in the sharepoint designer and then expand the list and open the Newform.aspx of the list to be validated As you can see in the image above the Newform.aspx of Validation list is being opened in the sharepoint Designer. Now right click on this Validation list web part in sharepoint Designer and choose Web Part properties. The properties dialog box will open for the Validation list here. Choose Hidden under layout and say ok. (This web part can be deleted as well, but due to some Known problems because of deletion it is best to hide this). Now click exactly underneath the hidden list web part and go to Insert->Sharepoint Controls-> Custom List Form… and Wizard will ask to choose a List or Docu