<script>

//1.创建和遍历二维数组

var info = new Array(new Array("Tom",13,155),new Array("Luck",11,152));

//空的二维数组

var arr = new Array(new Array(),new Array());

var num = [[1,3],[4,6]];

var empty = [[],[]];

</script>

<script>

var arr = [[12,45,98],[76,32,89,100],[100,100]];

//求和

//计算平均值

var sum = 0;

var n =0 ;//元素个数

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

{

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

{

sum+= arr[i][j];

n++;

}

}

/*

for(var i in arr)

{

for( var j in arr[i])

{

sum+= arr[i][j];

}

}

*/

var avg = sum/n;

console.log(arr);

console.log("二维数组和:"+sum);

console.log("二维数组元素个数:"+n);

console.log("二维数组平均值:"+avg);

</script>

//************************************************************************

<script>

var arr = new Array( new Array(1,2,3),new Array(4,5,6),new Array(7,8,9));

var sum = 0;

for(var i= 0;i<3;i++)

{

for(j=0;j<3;j++)

{

sum += arr[i][j];

}

}

console.log(sum);

</script>