小编Dan*_*ski的帖子

var
startx = 0,
starty = 0,
endx = 12,
endy = 100;

for(startx;startx <= endx; startx+=1){
        for(starty; starty <= endy; starty+=1){
            console.log(startx, endx, starty, endy);
     }
}

预期产量:

0, 12, 0, 100
0, 12, 1, 100
0, 12, 2, 100
...
0, 12, 100, 100
1, 12, 0, 100
1, 12, 1, 100
...
12, 12, 100, 100
;EOO

Chrome 39+上的输出

0, 12, 0, 100
0, 12, 1, 100
0, 12, 2, 100
...
0, 12, 100, 100

所以问题是第一个for循环不会遍历startx变量. …