function mascara(e,src,mask) {
if(window.event) {
_TXT = e.keyCode;
} else
if(e.which) {
_TXT = e.which;
}
if(_TXT > 47 && _TXT < 58) {
var i = src.value.length;
var saida = mask.substring(0,1);
var texto = mask.substring(i);
if(texto.substring(0,1) != saida) {
src.value += texto.substring(0,1);
}
return true;
} else {
if (_TXT != 8) {
return false;
} else {
return true;
}
}
}