function MM_formtCep(e,src,mask) {
    //IE
    if(window.event){
        _TXT = e.keyCode;
    }
    //Firefox
    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; 
        }
    }
}