I succeed by using two ajax function one for sending post request and another one is to send a mail like above.
$.ajax({
type:post,
url:urlfinal,
success:function(data){
}
});
$.ajax({
url:mail.php,
success:function(data){
}
});
but still have doubt why i am facing issue if i use mail.php in action attribute of form element. Any views friends?