function formMascara(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 = "#"; 
	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; 
	}
}
}