Ext 中文排序问题

Ext.data.Store.prototype.applySort = function(){
	if(this.sortInfo && !this.remoteSort){
		var s = this.sortInfo;
		var f = s.field;
		var st = this.fields.get(f).sortType;
		var fn = function(r1, r2){
			var v1 = st(r1.data[f]);
			var v2 = st(r2.data[f]);
			if(typeof(v1) == "string"){
				return v1.localeCompare(v2);
			}
			return v1 > v2 ? 1 : (v1 < v2 ? -1 : 0);
		}
		this.data.sort(s.direction, fn);
		if(this.snapshot && this.snapshot != this.data){
			this.snapshot.sort(s.direction, fn);
		}
	}
}