select 下拉框的选中项的change事件

HTML文件
  <span style="float: left;">类&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;型:&nbsp;&nbsp;
        <select id="type" class="easyui-combobox" name="type" style="width: 90px;" data-options="required:false">
             <option value="1" selected="selected">安心帮卖</option>
             <option value="2">同步拍</option>
        </select>
    </span>
    
    <span style="float: right; margin-left: 66px;">
    <span id="auctionsFlag" style="display:none;">拍卖会场次:&nbsp;
        <select id="auctionId" class="easyui-combobox" name="auctionId" style="width: 244px;" data-options="required:false">
            <!-- <option value="" selected="selected">"　"</option> -->
        </select>
    </span>
    <span id="aucTime">拍卖时间:&nbsp;&nbsp;
        <input  type="text" id="startDate" style="width:110px;" class="easyui-datebox"/>
        &nbsp;&nbsp;至&nbsp;&nbsp;<input type="text" id="endDate" style="width:110px;" class="easyui-datebox"/>
    </span>
        
</span>

JS文件
    var typeFlag = 0;
    $("#type").combobox({
        onChange: function (n,o) {
            if(n==1){
                hidden_change();
            }else{
                view_change();
            }
        }

    });
    
    function hidden_change(){
        typeFlag = 0;
        $("#auctionsFlag").css("display","none");
        $("#aucTime").css("display","block");
    }
    function view_change(){
        typeFlag = 1;
        $("#auctionsFlag").css("display","block");
        $("#aucTime").css("display","none");
    }