Sys.WebForms.PageRequestManager.getInstance().add_beginRequest(beginReq);
Sys.WebForms.PageRequestManager.getInstance().add_endRequest(endReq);

            function beginReq(sender, args) {
	            // shows the Popup 
	            $find(ModalProgress).show();
            }

            function endReq(sender, args) {
	            //  shows the Popup 
	            $find(ModalProgress).hide();
            } 

 //<script language="javascript" type="text/javascript">
            function PopupCars() {
//                var ancho=1200 
//                var alto=600 
//                var x=(screen.width-ancho)
//                var x=((screen.width-ancho)/2)
//                var y=((screen.height-alto)/2)
//                var params="'position: absolute,top=" + (y)+ ", left=" + (x) + ", height=" + alto + ", width=" + ancho + "'" 
//                window.open('/autos.htm', 'abre_autos_htm', params); 
                window.showModalDialog('/autos.aspx',"",'dialogHeight:500px;dialogWidth:800px;center:Yes;help:No;resizable: No;status:No;');


                }    
             function PopupCDW() {
                var ancho=800 
                var alto=450 
//                var x=(screen.width-ancho)
                var x=((screen.width-ancho)/2)
                var y=((screen.height-alto)/2)
                var params="'position: absolute,top=" + (y)+ ", left=" + (x) + ", height=" + alto + ", width=" + ancho + "'" 
//                window.open('/autos.htm', 'abre_autos_htm', params); 
                window.showModalDialog('/Rental_Policies.htm',"",'dialogHeight:450px;dialogWidth:670px;center:Yes;help:No;resizable: No;status:No;');
                }    
              
//</script>