function NumAscSort(a,b)
{
 return a - b;
}
function NumDescSort(a,b)
{
 return b - a;
}
var arr = new Array( 3600, 5010, 10100, 801); 
arr.sort(NumDescSort);
alert(arr);
arr.sort(NumAscSort);
alert(arr);

var myarray=["Apple", "Banana", "Orange"]
myarray.sort()

//by函数接受一个成员名字符串做为参数
//并返回一个可以用来对包含该成员的对象数组进行排序的比较函数
var by = function(name){
 return function(o, p){
  var a, b;
  if (typeof o === "object" && typeof p === "object" && o && p) {
   a = o[name];
   b = p[name];
   if (a === b) {
    return 0;
   }
   if (typeof a === typeof b) {
    return a < b "error");
  }
 }
}

var employees=[]
employees[0]={name:"George", age:32, retiredate:"March 12, 2014"}
employees[1]={name:"Edward", age:17, retiredate:"June 2, 2023"}
employees[2]={name:"Christine", age:58, retiredate:"December 20, 2036"}
employees[3]={name:"Sarah", age:62, retiredate:"April 30, 2020"}

employees.sort(by("age"));

//by函数接受一个成员名字符串和一个可选的次要比较函数做为参数
//并返回一个可以用来包含该成员的对象数组进行排序的比较函数
//当o[age] 和 p[age] 相等时，次要比较函数被用来决出高下
var by = function(name,minor){
 return function(o,p){
  var a,b;
  if(o && p && typeof o === 'object' && typeof p ==='object'){
   a = o[name];
   b = p[name];
   if(a === b){
    return typeof minor === 'function' "error");
  }
 }
}
employees.sort(by('age',by('name')));