动态获取selected的value值

两个select选项，第一个选项可以选1-9之间的数字，第二个选项可以选0到9之间的数字，要满足成人和儿童的总和不大于9，且一个成人最多带两名儿童

<div>

     <span>成人：</span>
     <select id="AdultNum">
     <option value="1">1</option>
     <option value="2">2</option>
     <option value="3">3</option>
     <option value="4">4</option>
     <option value="5">5</option>
     <option value="6">6</option>
     <option value="7">7</option>
     <option value="8">8</option>
     <option value="9">9</option>
     </select>

     <span>儿童：</span>
     <select id="ChildNum">
     <option value="0">0</option>
     <option value="1">1</option>
     <option value="2">2</option>
     <option value="3">3</option>
     <option value="4">4</option>
     <option value="5">5</option>
     <option value="6">6</option>
     <option value="7">7</option>
     <option value="8">8</option>
     <option value="9">9</option>
     </select>

</div>

当大于9或儿童大于成人的2倍的时候出现提示文案

//儿童和成人总数不超过9，且1名成人至多带2名儿童


$('#AdultNum').change(function () {
    var adultnum = $(this).val();
    PassengerNum(adultnum, '#ChildNum');
    });


$('#ChildNum').change(function () {
    var childnum = $(this).val();
    PassengerNum1(childnum, '#AdultNum');
});


var a_num = $('#AdultNum').val();
PassengerNum(a_num, '#ChildNum');

var c_num = $('#ChildNum').val();
PassengerNum(c_num, '#AdultNum');

function PassengerNum(num, id) {
    $(id).change(function () {
        var cnum = $(this).val();
        var sum = parseInt(num) + parseInt(cnum);
        var par = parseInt(num) * 2;
        if (sum > 9) {
            $('.psnum-waring').show();
            $('.psnum-waring').html('乘客总数不多于9人');
        } else if (cnum > par) {
            $('.psnum-waring').show();
            $('.psnum-waring').html('每名成人最多可携带2名儿童');
        } else {
            $('.psnum-waring').hide();
        }

    });
}

function PassengerNum1(num, id) {
    $(id).change(function () {
        var cnum = $(this).val();
        var sum = parseInt(num) + parseInt(cnum);
        var par = parseInt(cnum) * 2;
        if (sum > 9) {
            $('.psnum-waring').show();
            $('.psnum-waring').html('乘客总数不多于9人');
        } else if (num > par) {
            $('.psnum-waring').show();
            $('.psnum-waring').html('每名成人最多可携带2名儿童');
        } else {
            $('.psnum-waring').hide();
        }

    });
}

 这种写法太麻烦，优化js

var interTicketO = {}

interTicketO._PassengerNum=function(id1,id2) {
    var adultNum = Number($(id1).val());
    var childNum = Number($(id2).val());
    var html1 = '<span class="icon-waring"></span>乘客总数（不含婴儿）多于9人。';
    var html2 = '<span class="icon-waring"></span> 每名成人最多可携带2名儿童，暂不支持婴儿票在线预定。';

    $('.psnum-waring').hide();

    if ((adultNum + childNum) > 9) {
        $('.psnum-waring').show();
        $('.psnum-waring').html(html1);
        return;
    }
    if ((adultNum * 2) < childNum) {
        $('.psnum-waring').show();
        $('.psnum-waring').html(html2);
    }
}