function findObj(theObj, theDoc)
{
  var p, i, foundObj;
  
  if(!theDoc) theDoc = document;
  if( (p = theObj.indexOf("?")) > 0 && parent.frames.length)
  {
	theDoc = parent.frames[theObj.substring(p+1)].document;
	theObj = theObj.substring(0,p);
  }
  if(!(foundObj = theDoc[theObj]) && theDoc.all) foundObj = theDoc.all[theObj];
  for (i=0; !foundObj && i < theDoc.forms.length; i++) 
	foundObj = theDoc.forms[i][theObj];
  for(i=0; !foundObj && theDoc.layers && i < theDoc.layers.length; i++) 
	foundObj = findObj(theObj,theDoc.layers[i].document);
  if(!foundObj && document.getElementById) foundObj = document.getElementById(theObj);
  
  return foundObj;
}

function teclaEvento(evento) {
	if (window.event) // IE  //(evento.keyCode)
		return evento.keyCode;
	else
		return evento.which;
}

function numeros(e)
{
	//ej: onkeypress="return numeros(event);"
	var keynum;
	var keychar;
	var numcheck;
	var res;
	
	keynum = teclaEvento(e);
	//alert (keynum);
	if ((keynum != undefined) && (keynum != 9) && (keynum != 0) && (keynum != 8) && (keynum != 13)) {
		keychar = String.fromCharCode(keynum);
		numcheck = /\d/
		res = numcheck.test(keychar);
	} else {
		res = true;
	}
	
	if (!res) {	alert ('Solamente puede ingresar números en este campo'); }
	return res;
}