function formatTel(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; }
}
}