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;
	}
}