JS遍历二维数组

 //求平均数

 var pjs=[

         ['小明',87],

         ['小红',81],

         ['小花',97],

         ['小天',76],

         ['小张',74],

         ['小小',94],

         ['小西',90],

         ['小武',76],

         ['小迪',64],

         ['小曼',76]

 ]

 var i,j;

 var sum=0;

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

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

   {

       if(j==pjs[i].length-1)

       {

           sum+=pjs[i][j];

       }

   }

 }

 sum=sum/pjs.length

 document.write(sum+"<br />");