// JavaScript Document
function IsEmpty(FieldValue)
{
  return ((FieldValue == null)||(FieldValue == ""))
}

function SeleccionaOtro( ThisObject, Target )
{
index = ThisObject.selectedIndex;
if( index > 0)
	{
	valor = ThisObject.options[index].value;
	if (valor == 0) 
	  {
	  Target.ReadOnly = false;
	  Target.value = "";
	  Target.focus();
	  }
	else
	  {
 		Target.value = ThisObject.options[index].text;
	  	Target.ReadOnly = true;
	  }
	}
}