1. Client-side is faster than server-side as the networking time from client to server is saved
2. server-side is done on the server. Then the server converts the data into an html page and sends to the browser.
3. server-side is more secure as the user cannot see the code even he does a view-source.

Client side validation is processed the client side before submitting the form. The advantage of using the client side validation is it reduces the netork trafiic since the validation is processed in the client machine itself. Eg email isnumeric isdate etc.

Server side validation is processed in the server. Some data cannot be validated in the client side and it has to be validated in the server side. Eg Date between the two dates in the database.

- Client side validation eliminates the round trip for the sake of any validation

- Server side validation is required since the validation that happens at the server end and can not be tampered with. Client side validation happens at the client machine using the Javascript which can be manipulated. For any important validations it is not safe to do only in the client side.

- Client side validation happens usually using javascript for compatibility across browsers. VB script can also be used but it will be working in the IE browser only and throwup errors in other browsers.

- Server Side validation is done using VB script usually