Js中的Array排序

var fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits.sort();
结果：
[Apple,Banana,Mango,Orange]
升序
var points = [40,100,1,5,25,10];
points.sort(function(a,b){return a-b});
结果：
1,5,10,25,40,100
降序
var points = [40,100,1,5,25,10];
points.sort(function(a,b){return b-a});
100,40,25,10,5,1