Question

我有一个脚本，每次倒计时达到0时都会替换一个图像。虽然我想知道是否可能，以及如何，我可以获得这些图像（我只是按顺序列出）每次随机化页面是刷新等。

以下是所有代码（图像位于“//填写此数组中的图像”之前）：

<div id="counter_2" class="counter">     
    <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.3/jquery.min.js" type="text/javascript" charset="UTF-8"></script>
    <script src="js/jquery.countdown.js" type="text/javascript" charset="UTF-8"></script>
    <script type="text/javascript">
        <!-- The ready() function will force the browser to run wait running the javascript until the entire page has loaded -->
        $(document).ready(function() {
        // The jquery code for constructing and starting the counter
        // has been wrapped inside a function so we can call it whenever we want to
        function startCounter(imageLoader){
            $('#counter_2').countdown({
                 image: 'img/digits.png',
                 startTime: '00:10',
                 timerEnd: function(){ callback(imageLoader) },
                 format: 'mm:ss'
            })
        }
        // Takes care of whatever need to be done everytime
        function callback(imageLoader){
            // Replace image
            $('#image').attr('src', imageLoader.nextImage());
            $('#counter_2').empty(); // Clear the finished counter, so a new can be constructed in its place
            startCounter(imageLoader); // Construct a new counter and starts it
        }
        function ImageLoader(images){
            this.images = images;
            this.current = 0;                 
            this.nextImage = function(){
                this.current = (this.current+1) % this.images.length;
                return this.images[this.current];;
            }
        }
        // Fill in images in this array
        imageLoader = new ImageLoader(['img/wallpapers/2.jpg', 'img/wallpapers/3.jpg', 'img/wallpapers/4.jpg', 'img/wallpapers/5.jpg', 'img/wallpapers/6.jpg', 'img/wallpapers/7.jpg', 'img/wallpapers/9.jpg', 'img/wallpapers/10.jpg', 'img/wallpapers/11.jpg', 'img/wallpapers/12.jpg', 'img/wallpapers/13.jpg', 'img/wallpapers/14.jpg',  'img/wallpapers/15.jpg', 'img/wallpapers/16.jpg', 'img/wallpapers/17.jpg', 'img/wallpapers/18.jpg', 'img/wallpapers/19.jpg', 'img/wallpapers/20.jpg', 'img/wallpapers/21.jpg', 'img/wallpapers/22.jpg', 'img/wallpapers/23.jpg', 'img/wallpapers/24.jpg', 'img/wallpapers/25.jpg', 'img/wallpapers/26.jpg', 'img/wallpapers/27.jpg', 'img/wallpapers/28.jpg', 'img/wallpapers/29.jpg', 'img/wallpapers/30.jpg', 'img/wallpapers/31.jpg', 'img/wallpapers/32.jpg', 'img/wallpapers/33.jpg', 'img/wallpapers/34.jpg', 'img/wallpapers/35.jpg', 'img/wallpapers/36.jpg', 'img/wallpapers/37.jpg', 'img/wallpapers/38.jpg', 'img/wallpapers/39.jpg', 'img/wallpapers/40.jpg', 'img/wallpapers/41.jpg']);
        startCounter(imageLoader); // Set everything off! (Construct a new counter and starts it)
        });       
    </script>
<div id="middle_wallpaper-actual">              
            <img id="image" src="img/wallpapers/1.jpg" alt="wallpapers">                
          </div>

Answer 1

替换

this.current = (this.current+1) % this.images.length;

与

this.current = Math.floor(Math.random() * this.images.length);

Answer 2

您可以使用Math.random函数生成随机数。例如，要生成0和9之间的随机数，您可以执行以下操作：

var num = Math.floor(Math.random() * 10);

我已经实现了一个ImageLoader，它会返回随机图像，永远不会返回相同的图像，直到它们全部显示。

http://jsfiddle.net/dUZSZ/2/

function ImageLoader(images) {
    this.images = images;
    this.usedIndexes = {};
    this.displayedCount = 0;
}

ImageLoader.prototype.nextImage = function () {
    var self = this,
        len = self.images.length,
        usedIndexes = self.usedIndexes,
        lastBatchIndex = self.lastBatchIndex,
        denyLastBatchIndex = self.displayedCount !== len - 1,
        index;

    if (this.displayedCount === len) {
        lastBatchIndex = self.lastBatchIndex = self.lastIndex;
        usedIndexes = self.usedIndexes = {};
        self.displayedCount = 0;
    }

    do {
        index = Math.floor(Math.random() * len);
    } while (usedIndexes[index] || (lastBatchIndex === index && denyLastBatchIndex));

    self.displayedCount++;
    usedIndexes[self.lastIndex = index] = true;

    return self.images[index];
};

js / jquery：如何随机化图像

2 个答案: