function Popup(url)
    {
        window.open(url,'Popup','outerWidth=650,width=400,Height=600,innerWidth=450,resizable,toolbar=no,scrollbars=yes');
    }
    
      function noPostBack(sNewFormAction)
    {
        document.forms[0].action = sNewFormAction;
        document.forms[0].__VIEWSTATE.name = 'NOVIEWSTATE';
    }

  function checkenter(evt){
        var nav4 = window.Event ? true : false; 
        var key = nav4 ? evt.which : evt.keyCode;
        if (key==13)
        {
            alert('Despúes de Capturar el RFC presione el botón Ingresar');
            return false;
        }
        else
        {
            return true;
        }
    }
       
       function checkenterNums(evt,ctl){
        var nav4 = window.Event ? true : false; 
        var key = nav4 ? evt.which : evt.keyCode;
        if (key==13)
        {
            return false;
        }
        else
        {
            var nav4 = window.Event ? true : false; 
            var key = nav4 ? evt.which : evt.keyCode;
            return (key<=13 || (key>=48 && key<=57));
            //return true;
        }
    }
    
 function Mayusculas(evt)
 {
    var text = evt.value; 
    evt.value= text.toUpperCase();
 }
 
 function isEmailAddress(theElement, nombre_del_elemento )
	{
		var s = theElement.value;
		var filter=/^[A-Za-z][A-Za-z0-9_.]*@[A-Za-z0-9-_]+\.[A-Za-z0-9_.]+[A-za-z]$/;
		if (s.length == 0 ) return true;
	   if (filter.test(s))
	      return true;
		  
	   else
	     alert("Favor de capturar un correo electrónico valido.");
		theElement.focus();
		return false;
		
}