Asp.Net has  few validation control  like 
campare , requirefield , rang ,regulorexpression and custom 

u can use any validation control with html ,asp control

Asp.net validation control are by default cilde side 
validation .
 and the cliend side validation is better blz it's reduse 
the burdon to the server

Hi Jiten, you're mistaken bydefault all the asp.net 
controls are server controls that runs server side, so 
validation controls do. To reduce the burden on the server 
we will use javascript validation which will be done client 
side.

how do you do validations in vb.net project

ASP.net has some validation controls which r used for validation of entry in the textboxes,dropdown & other controls etc.
These Validation Controls r:-
1> Required field validator.
2> Regular Expression field validator.
3> Range Validator.
4> Compare validator.
5> Custom field validator.
6> Validation field summary(used to display error messages).

Client side validation is better than that of server side validation b'coz it reduces the load on server by using client side validation & by doing this server performance increases & there responsivess is efficient....