I know many posts discussed about it. but I still can't find any solution works.
my ASPX CODE
<asp:Button ID="Booking1Btn" runat="server" CssClass="col-8 SureButton" Text ="NEXT" OnClientClick="javascript: return calcRoute()" OnClick="Booking1Btn_Click" />
if calcRoute() all route return false. the calcRoute() working fine, but onClick not fire. if calcRoute() return true, OnClick fire. but calcRoute() not working.
I have try OnClientClick="if (!calcRoute()) { return false; }" and OnClientClick="calcRoute(); return false; ". but all same, after onClientClick, onClick not fire.
why this rule not working,
calcRoute return true, onClick fired,
calcRoute return false, onClick not fired.