よく使うjsは対象を内蔵します.

1.    
concat()//     
slice(startIndex,endInex)//     (    ，   endIndex)
substring(start,stop)// 2   5  
substr(start,length);// start  ， 5      
lastIndexOf(".")//      "."     
2.     
getFullYear();
getDate();
3. array  (  java  list stack)
var as  = new Array();
as.push(11);
as.push(22);
alert(as);

as = new Array(11,22,33,"111","222");
alert(as);
//            
as = ["11",12,1,2,3];
alert(as);
//    join          
alert(as.join("---"));//  11---12---1---2---3

sort()//          

reverse()//        

as.splice(2,0,31,32);//      2       0   ，        31

 32