sort()排序

var ary = [8,9,10,3],

 	compare = function(a,b){

		return b.age-a.age;
 	},

	g = [

 			{
 				name:"jim",

 				age:29
 			},

 			{
				name:"tom",

 				age:15
 			},

 			{
 				name:"mary",

 				age:20
 			}

 	];

 	g.sort(compare);

 	console.log(g);