Validating user input in asp net web pages

Client Side Validation does not require a postback but server side validation requires a postback.

But when I try to use it in my main project, the errors pop up (context errors). This may be an undesired position as it is visually more impressive if a validation text is located next to the box in question.You can force all validators to appear in the same location by setting the display property from The Page object accessible from the C# code behind has a property called Is Valid which can be used to determine if there are validation errors on the page. NET Web Pages with Web Matrix section of the Wrox Programmer to Programmer discussions.

This should work, unless Helpers is broken, or in the wrong place.

Server side validation is mandatory but client side validation is not mandatory because it happens on client's browser and one can easily bypass it by simply turn off Javascript on the browser.