function isEnter(evt, theForm) {
  evt = (evt) ? evt : ((event) ? event : null);
  if(!evt) return true;
  var val = (evt.keyCode) ? evt.keyCode : evt.which;
  return (val == 13);
}

function addLoadEvent(fn) {
  var curFn = window.onload;
  window.onload = (typeof window.onload != 'function') ? fn : function(){curFn();fn();}
}
  
function checkSubmit(evt, theForm) {
  evt = (evt) ? evt : ((event) ? event : null);
  if(!evt) return true;
  var val = (evt.keyCode) ? evt.keyCode : evt.which;
  if(val == 13) theForm.submit();
  else          return true;
}