//var a = new Array(5);
//Array.prototype[0] = 0;
//a[1] = 1;
//a[2] = 2;
//a[3] = undefined;
//Array.prototype[4] = 4;
//a.length;
5
//var b = a.reverse();
//(contents of a);
undefined
2
1
undefined
4
//(contents of b);
undefined
2
1
undefined
4
//Array.prototype[4] = 999;
//(contents of b);
undefined
2
1
undefined
999
