is it necessary to do server side validation after client side validation with asp.net web site?

Question

i am developing an asp.net site and i made validation for the web form using javascript and validation controls.

my question is: is it necessary before inserting data into the database to validate them in server side too or it's not??

Answer 1

Yes, it is.

Client-side validation can be trivially bypassed by disabling Javascript.

Answer 2

Yes, also validating on the server is good practice.

This is because any user can take your HTML page and modify it anyway they choose, removing any and all restrictions and limitations. Double checking on the server prevents such abuse.

Answer 3

Better Use .net Validation .

http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.basevalidator.enableclientscript.aspx