function mascara_placa(el){
 	var mydata = '';
 	mydata = mydata + el.value;
 	while(mydata.length < 4) {
 		mydata = mydata.toUpperCase();
 		el.value = mydata;
 		if (mydata.length == 3) {
 			mydata = mydata + '-';
 			el.value = mydata;
 		}
 		break;
 	}
 }