function Volver()
{
	history.go(-1);
}

function newPopup(url) 
{
	popupWindow = window.open
	(
		url,'popUpWindow','height=768,width=1024,left=170,top=10,resizable=no,scrollbars=yes,toolbar=no,menubar=no,location=no,directories=no,status=yes'
	)
}

function hideTextUser(id) {
  var element = document.getElementById(id);
  if (element.value == "Usuario") {
	element.value = "";
	element.className = "ct_1_focused";
  }
}

function hideTextPass(id) {
  var element = document.getElementById(id);
  if (element.value == "Clave") {
	element = changeInputType(element, 'password');
	element.className = "ct_2_focused";
	element.value = "";
	element.focus();
	element.select();
  }
}

function showTextUser(id) {
  var element = document.getElementById(id);
  if (element.value == "") {
	element.className = "ct_1";
	element.value = "Usuario";
  }
}

function showTextPass(id) {
  var element = document.getElementById(id);
  if (element.value == "") {
	element = changeInputType(element, 'text');
	element.value = "Clave";
	element.className = "ct_2";
  }
}

function changeInputType(oldObject, oType) {
  var newObject = document.createElement('input');
  newObject.type = oType;
  if (oldObject.size) newObject.size = oldObject.size;
  if (oldObject.value) newObject.value = oldObject.value;
  if (oldObject.name) newObject.name = oldObject.name;
  if (oldObject.id) newObject.id = oldObject.id;
  if (oldObject.onblur) newObject.onblur = oldObject.onblur;
  if (oldObject.onclick) newObject.onclick = oldObject.onclick;
  if (oldObject.onfocus) newObject.onfocus = oldObject.onfocus;
  if (oldObject.className) newObject.className = oldObject.className;
  oldObject.parentNode.replaceChild(newObject, oldObject);
  return newObject;
}