unable to call the code behind of button click after java script function is called

i have a form it has to be validated before code behind of button fires

< asp: button id="btn1" runat="server" usesubmittbehaviour="false" onclientclick="validate(this) return"/>

and there is click event in code behind, but when the validate ret开发者_如何学Pythonurns true click event of button not firing..

You should change

validate(this) return

with

return validate(this)

in the onclientclick attribute