Uncaught TypeError: Cannot read property 'children' of undefined

[ntzsl110]

TreeTable.prototype.refresh = function (id, data) {
var components = this.getComponents().$table;
var $table = components.$table;

    var d, $tr;
    if (id != undefined) {
        d = getDataById(this.getData(), id, this.options.tree);
        $tr = $table.children('tbody').children('tr[data-id="' + id + '"]');
    }
   ......

}
大佬，麻烦抽时间看下$table，insTb.refresh(id,data);更新提示错误 Cannot read property 'children' of undefined。