如何在一个阵列中加载多张要褪色的图像？

Question

I have the following code which suppose to load couple of images and then to fade them. But instead to load all images on each fade it loads the same image every time. Does anyone have any idea?

http://jsfiddle.net/7kacz43o/8/

var img, i,
    imageCount = [1,2,3,4],
    div = document.getElementById('foo');
console.log(imageCount.length);
for(i = 1; i <= imageCount.length; i++){
    img = new Image();
    img.onload = function() {
        div.appendChild(img);
    };
    img.src = 'http://tdhdemo.com/frames/frame_' + i + '.jpg';
    img.id = "top";
}

Answer 1

You reuse img inside onload , which means when the for runs for the next index, img will be overwritten. In the onload event only the last img will be appended to the div (4 times, but that results in one image tag).

Since you attach the onload function on the img itself, you can use this to reference the image:

img.onload = function() {
    div.appendChild(this);
};

---

Another recommendation: Instead of using an array and its length to power your for loop, why not use a count variable directly?

var imageCount = 4;
...
for (i = 1; i <= imageCount; i++) {