ASP.NET OnClientClick="return false;" doesn't work
for some reason, although I didn't have any jquery event handlers attached, it didn't work.
What actually worked was:
OnClientClick="if (validate_form() == false) return(false);"
Do you have a click event handler (registered via jquery) which returns true
? In that case, the return value of OnClientClick
is ignored.
Have a look at my question (and answer): Why doesn't returning false from OnClientClick cancel the postback
Try changing it to
OnClientClick="ValidateMail(); return false;"