通过 javascript 为 div 分配背景在 jsfiddle.net 中有效，但在代码中无效

Question

https://copy.com/XPfxgQeHF78d8lgw 是文件的链接 小提琴的链接在这里http://jsfiddle.net/LgjzvcpL/9/

我已经尝试在现实生活版本中消除所有可能的内容，但这无济于事

document.getElementById("image").style.backgroundImage = "url(" + dir + images[randomCount] + ".jpg" +  ")"; 

Answer 1

您需要在加载 DOM 后运行您的代码。将它移到</body> 标记之后，或者在window.onload 处理程序中运行它。

另外，你的赋值语句需要以;结尾，而不是,。

window.onload = function() {
    var dir = 'http://seriousphotography.co.uk/HD-Site/images/album/01/';
    var randomCount = Math.round(Math.random() * (imgCount - 1)) + 1;
    var images = new Array;
    images[1] = "01";
    images[2] = "02";
    images[3] = "03";
    images[4] = "04";
    images[5] = "05";
    images[6] = "06";
    images[7] = "07";
    images[8] = "08";
    images[9] = "09";
    images[10] = "10";
    document.getElementById("image").style.backgroundImage = "url(" + dir + images[randomCount] + ".jpg" +  ")"; 
};

这样写会更简单：

window.onload = function() {
    var dir = 'http://seriousphotography.co.uk/HD-Site/images/album/01/';
    var images = ["01", "02", "03", "04", "05", "06", "07", "08", "09", "10"];
    var randomCount = Math.floor(Math.random() * images.length);
    document.getElementById("image").style.backgroundImage = "url(" + dir + images[randomCount] + ".jpg" +  ")"; 
};

见Get random item from JavaScript array

使用类和 jQuery，它会是：

$("#image").addClass("image"+images[randomCount]);

小提琴：http://jsfiddle.net/barmar/LgjzvcpL/12/