自学的JS吗,请教一下这段代码的意思,多谢!
function turn(value) {
if (value != null) {
flag = value - 2;
}
if (flag < obj2.length - 1)
flag++;
else
flag = 0;
obj1.style.top = flag * (-404) + "px";
for (var j = 0; j < obj2.length; j++) {
obj2[j].style.backgroundColor = "#ffffff";
}
obj2[flag].style.backgroundColor = "#666666";
}