var ns = (document.layers)? true:false;
var ie = (document.all)? true:false;
if (window.document.captureEvents!=null)
	window.document.captureEvents(Event.KEYPRESS);
window.document.onkeypress = checkReturn;

function checkReturn(e)
{
   keyPressed = "";
   if (ns)
	keyPressed = String.fromCharCode(e.which);
   else if (ie)
	keyPressed = String.fromCharCode(window.event.keyCode);
   if (keyPressed=="\r" || keyPressed=="\n")
	  enviar();
}