Asp.net Form : I just want an explanation

Hy guys,


This page (http://msdn.microsoft.com/en-us/magazine/cc163736.aspx) states something interesting: "If a non-container control (TextBox, for example) is placed outside the form tag, an HttpException is thrown at run time (no check is made for this at compile time)." This makes me think that, if I place a container control (as a PlaceHolder, MultiView, or some other) outside of a form tag, it will not throw an exception. Right?



I'm asking that because of the following: I'm now responsible for some web projects built by another company. And, in the master page, they created an HTML form to provide search functionality, and right below, they put an asp.net form to contain only a ScriptManager (ajax.net) and a user control. AFTER that (after the asp.net form tag has been closed) they place the asp:ContentPlaceHolder control. And this runs fine.



Now, inside the pages that reference this master page, they don't ever use ...