submit problem

very strange thing, i created a form then when i press enter nothing happen unless i press the mouse on the submit button, is this problem a usual problem? how to solve

Did you not try the example I posted here (http://www.codingforums.com/showthread.php?t=49399)?

YES,it did not work, but i discovered it now that the problem may lie in
if($_POST['submit']) , when i submit to different page it work, but i submit to the page itself it fails