var arr = {};
for (var x = 1; x < 10; x++) {
    for (var y = 1; y < 10; y++) {
        arr[[x, y]] = x * y;
    }
}

alert(arr[[3, 9]]);

------解决方案--------------------


------解决方案--------------------
当有啦，只要你想要三维四维都有。定义和一维是一样的如：
  声明： var user = new Array();
  user[0] = new Array("Tom","Beijing","1101");
  user[1] = new Array("Tom1","Beijing1","11011");
  取数据：alert(user[0][1]);