修改ext-all.js源代码： 定义全局var bool = true; var cilIndex=0; 修改onHeaderClick方法：
onHeaderClick: function(b, a) { if (this.headersDisabled || !this.cm.isSortable(a)) { return } b.stopEditing(true); if(cilIndex == a){ bool = !bool; }else{ cilIndex = a; } var str = bool?"DESC":"ASC"; b.store.sort(this.cm.getDataIndex(a),str) },
