function checkVoteOptions(id) {
    var ul = document.getElementById(id);
    var checked = false;
    for (i = 0; i < ul.childNodes.length; i++) {
        var option = ul.childNodes[i].childNodes[0];
        if (option.checked) {
            checked = true;
            break;
        }
    }
    if (!checked) {
        alert("请选择投票项目再尝试投票操作!")
    }
    return checked;
}