bootstraptable 删除之后下拉框无法即时再次加载

$.get('del', {ids : selections}, function(data) {
    bootbox.alert('执行成功!');
    $table.bootstrapTable('refresh');
    $("#updeptId").empty();
});

需要在删除之后先执行empty();清空下拉框的方法，之后重新发送请求，请求下拉框中的值

<div class="col-xs-6">
    <label for="updeptId" class="control-label">上级部门:</label>
    <select class="form-control select2" id="updeptId" name="updeptId" style=" 100%">
    </select>
    <label class="error" for="updeptId"></label>
</div>
<script>
var select2FormValue = {};
select2FormValue.updeptId='';
$("#modalForm").on("shown.bs.modal", function() {
    initDept();
});

$("#btnadd").click(function() {
    select2FormValue.updeptId="";
    $('#modalForm').modal('show');
});
function initDept() {
$.getJSON("${pageContext.request.contextPath}/select", {},function(data) {
    select2Data = data.items;
    $("#updeptId").select2({
        data : select2Data,
    dropdownParent : $('#modalForm'),
    placeholder:'请选择'
    });
    $("#updeptId").val(select2FormValue.updeptId).trigger('change');
});
} 
</script>