var validaEmail = function(mail){
    var er = new RegExp(/^[A-Za-z0-9_\-\.]+@[A-Za-z0-9_\-\.]{2,}\.[A-Za-z0-9]{2,}(\.[A-Za-z0-9])?/);

    if(typeof(mail) == "string"){
        if(er.test(mail)){return true;}
    }else if(typeof(mail) == "object"){
        if(er.test(mail.value)){
            return true;
                               }
    }else{
        return false;
         }
};