二维数组

例子：矩形反转：

<script>

         var arr=[[1,1,1,1,1],[2,2,2,2,2],[3,3,3,3,3],[4,4,4,4,4],[5,5,5,5,5]];

        

         for(var i=0;i<arr.length;i++){

                   for(var j=0;j<arr[i].length;j++){

                            document.write(arr[i][j]);

                            }

                   document.write("<br>");

                   }

                  

         document.write("<br>");

        

         for(var i=0;i<arr[0].length;i++){

                   for(var j=0;j<arr.length;j++){

                            document.write(arr[j][i]);

                            }

                   document.write("<br>");

                   }

</script>

输出效果：