javascript指定排序方式

<pre name="code" class="javascript">    		//测试数据
var data  = [{name:"zhangsan",age:21},{name:"lisi",age:22},{name:"wangwu",age:19}];

function createComparisonFunction(propertyName,orderBy_DESC){
return function (object1,object2){
var value1 = object1[propertyName];
var value2 = object2[propertyName];
if(orderBy_DESC){//降序
if(value1>value2){
return -1;
}else if(value1<value2){
return 1;
}else{
return 0;
}
}else{//默认升序
if(value1<value2){
return -1;
}else if(value1>value2){
return 1;
}else{
return 0;
}
}
}
}
//指定排序方式，我这里是按照名字降序，第二个参数有值则降序，只传入第一个参数则升序
data.sort(createComparisonFunction("name",1))
//打印结果
for(var i = 0 ;i<data.length;i++){
document.write(data[i].name+"\n\n");
}