function KeyDownHandler(e, btn)
  {
  	var eventInstance = window.event ? event : e;

  	if (window.event) // IE
  	{
  		if (eventInstance.keyCode == 13)
  		{
  			eventInstance.returnValue = false;
  			eventInstance.cancel = true;
  			var obj = document.getElementById(btn);
  			obj.click();
  			return false;
  		}
  	}
  	else if (eventInstance.which) // Netscape/Firefox/Opera
  	{
  		if (eventInstance.which == 13)
  		{
  			eventInstance.returnValue = false;
  			eventInstance.preventDefault();
  			eventInstance.cancelBubble = true;
  			var obj = document.getElementById(btn);
  			obj.click();
  			return false;
  		}
  	}
  }

  function kH(e)
  {
	//var pK = e ? e.which : window.event.keyCode;
	//return pK != 13;
  if ((event.which ? event.which : event.keyCode) == 13) {
		//if ((event.which && event.which == 13) || (event.keyCode && event.keyCode == 13))
		//alert(document.getElementById('_ctl0:ContentPlaceHolderBody:Checkout:ShippingInformation:TextboxAddress').id);
		if (document.getElementById('_ctl0:ContentPlaceHolderBody:Checkout:ShippingInformation:TextboxAddress') == null && document.getElementById('_ctl0:ContentPlaceHolderBody:Checkout:BillingInformation:TextboxAddress') == null) {
			event.keyCode=0;
			event.returnValue = false;
			event.cancel = true;             // these two lines stops the event activated by the enter

			alert('Please click on a Button to Continue.');
			return false;
			}
		else
			return true;
    }
}
document.onkeypress = kH;
if (document.layers) document.captureEvents(Event.KEYPRESS);