js sort根據數值大小自動排序（轉）

var arrDemo = new Array();

 arrDemo[0] = 10;
 arrDemo[1] = 50;
 arrDemo[2] = 51;
 arrDemo[3] = 100;

 arrDemo.sort(); //調用sort方法后，數組本身會被改變，即影響原數組

 alert(arrDemo);//10,100,50,51 默認情況下sort方法是按ascii字母順序排序的，而非我們認為是按數字大小排序

 arrDemo.sort(function(a,b){return a>b?1:-1});//從小到大排序

 alert(arrDemo);//10,50,51,100

 arrDemo.sort(function(a,b){return a<b?1:-1});//從大到小排序

 alert(arrDemo);//100,51,50,10