下拉框的清空

    //注册重置按钮点击事件
            $('#bizGroupMemberTaskQuery_admin_query').find('#btn-reset').on('click',function(){
                //重置组名查询条件
            //    $('#bizGroupMemberTaskQuery_admin_query').find("#groupName").val("");
                $('#bizGroupMemberTaskQuery_admin_query').find("#groupName option").each(function () {
                    $(this).removeAttr("selected");
                });
                $('#bizGroupMemberTaskQuery_admin_query').find("#groupName option").each(function () {
                    var $option = $(this);
                    var value = $option.val();
                    if (value == "") {
                        $(this).attr("selected", "selected");
                    }
                });
                //重置组任务类型查询条件
            //    $('#bizGroupMemberTaskQuery_admin_query').find("#groupTaskType").val("");
                $('#bizGroupMemberTaskQuery_admin_query').find("#groupTaskType option").each(function () {
                    $(this).removeAttr("selected");
                });
                $('#bizGroupMemberTaskQuery_admin_query').find("#groupTaskType option").each(function () {
                    var $option = $(this);
                    var value = $option.val();
                    if (value == "") {
                        $(this).attr("selected", "selected");
                    }
                });
                //重置开始日期查询条件
                $('#bizGroupMemberTaskQuery_admin_query').find("#startDate").val("");
                //重置结束日期查询条件
                $('#bizGroupMemberTaskQuery_admin_query').find("#endDate").val("");
                //重置姓名查询条件
                $('#bizGroupMemberTaskQuery_admin_query').find("#userName").val("");
                /* bizGroupMemberTaskQuery.initSelect();
                bizGroupMemberTaskQuery.dt.draw(); */
            });

initSelect: function(){
            //初始化组名下列框
            ajax_jsonp("/app/bl/bizGroupMemberQuery/getGroupName/",null,function(response) {
                if(!checkResponseData(response) || !isNotNull(response.data[0]))
                    return;
                var region = response.data[0];
                var queryDiv = $("#bizGroupMemberTaskQuery_admin_query").find("#groupName");
                queryDiv.empty();
                queryDiv.append("<option value=''>请选择</option>");
                $.each(region,function(index,obj){
                    queryDiv.append("<option value='"+obj.groupName+"'>"+obj.groupName+"</option>");
                 });
            },null,"GET");
            //初始化组任务类型下列框
            ajax_jsonp("/app/bl/bizGroupMemberQuery/getGroupTaskType/",null,function(response) {
                if(!checkResponseData(response) || !isNotNull(response.data[0]))
                    return;
                var region = response.data[0];
                var queryDiv = $("#bizGroupMemberTaskQuery_admin_query").find("#groupTaskType");
                queryDiv.empty();
                queryDiv.append("<option value=''>请选择</option>");
                $.each(region,function(index,obj){
                    queryDiv.append("<option value='"+obj.taskName+"'>"+obj.taskName+"</option>");
                 });
            },null,"GET");
        }

<div class="ne-div-query horizon-list"
    id="bizGroupMemberTaskQuery_admin_query">
    <div class="am-input-group am-input-group-lg">
        <span class="am-input-group-label">组名</span> 
        <!--<input type="text"-->
               <!--name="groupName" class="am-form-field" placeholder="请输入组名"-->
               <!--id="groupName"  maxlength="255"/>-->
        <!--</input>-->
        <select data-am-selected="{searchBox: 1}" id="groupName" name="groupName">
            <option value="">点击选择....</option>
        </select>

    </div>
    <div class="am-input-group am-input-group-lg">
        <span class="am-input-group-label">组任务类型</span> 
        <!--<input type="text"-->
               <!--name="groupTaskType" class="am-form-field" placeholder="请输入组任务类型"-->
               <!--id="groupTaskType"  maxlength="255"/>-->
        <!--</input>-->
        <select data-am-selected="{searchBox: 1}" id="groupTaskType" name="groupTaskType">
            <option value="">点击选择....</option>
        </select>
    </div>
    <div class="am-input-group am-input-group-lg" >
            <span class="am-input-group-label">开始日期</span>
            <div class="am-form-group am-form-icon am-inline-block">
                <i class="am-icon-calendar"></i> <input type="text"
                name="startDate" class="am-form-field data-am-datepicker" placeholder="请输入开始日期" id="startDate"/>
        </div>
    </div>
    <div class="am-input-group am-input-group-lg endDate">
        <span class="am-input-group-label">至</span>
        <div class="am-form-group am-form-icon am-inline-block">
            <i class="am-icon-calendar"></i> <input type="text"
            name="endDate" class="am-form-field data-am-datepicker" placeholder="请输入结束日期" id="endDate"/>
        </div>
    </div>
    <div class="am-input-group am-input-group-lg">
        <span class="am-input-group-label">姓名</span>
        <input type="text"
            name="userName" class="am-form-field" placeholder="请输入姓名"
            id="userName"  maxlength="255"/>
    </div>
    <button type="button" class="am-btn am-btn-primary" id="btn-query">查询</button>
    <button type="button" class="am-btn am-btn-primary" id="btn-reset">清空</button>

</div>