Only One Server-Side Form per Page

One significant limitation of the ASP.NET framework is that you can have only one server-side form in a page. For example, many Web sites have a single page that enables new users to register and existing users to log in. You cannot easily create this type of page with the ASP.NET framework.

The ASP.NET framework does not allow you to create a single page with two forms that both take advantage of ASP.NET functionality, such as form validation and view state. You must divide the single page into two pages.

This restriction does not apply to normal HTML forms; it applies only to server-side forms. You can have as many standard client-side forms in a page as you wish.