How to Use ASP.NET Validators to Works Like Warnings ant Not Prevent PostBack

I have asp.net Page Have Some Controls Textboxes ...to Fill Data ....all of them has Validators....and at the page bottom i have ...SaveButton... I want all validators to work in Client Side ...................."but some of them shall prevent PostBack ....and Others Shall Not Prevent Auto PostBack Even if ....The Validation is Fired ......So How Can I do that ...............All Validation Work in Client Side but some of them Prevent Post Back and The Other Not Prevent PostBack
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