In my form there are 2 fields name and password. through java script function chek() I am checking it whether it is filled or not but I am executing that function on onclick event of submit button. so request goes to server. though I am returning false if I have not filled the fields. Is there any mechanism to stop the request without using ajax or without calling that function on another event.
How are you calling this function in the onSubmit handler? It needs to be called like "return validate_email(...)", not "validate_email(...)".
Also make sure that you return something from that function in every case, not just in the negative.