//e is event object passed from function invocation
function checkEnter(e) {
   // window.alert("checkEnter");
   // literal character code will be stored in this variable
   var characterCode 
   
   //if which property of event object is supported (NN4)
   if(e && e.which) { 
      e = e
      characterCode = e.which //character code is contained in NN4's which property
   }
   else {
      e = event
      characterCode = e.keyCode //character code is contained in IE's keyCode property
   }
   // window.alert("characterCode="+characterCode);
   //if generated character code is equal to ascii 13 (if enter key)
   if ((characterCode == 13) || (characterCode == 1) || (characterCode == 0)) { 
      // submit the form
	  // window.alert("submit");
	  document.forms[0].submit() 
      return false
   }
   else {
      return true
   }
}