加载图像后重定向

本文介绍了加载图像后重定向的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

所以我最近开发了一个网站，问题是每个页面的背景都是图像，因此，在较慢的连接上（某些目标受众的情况），图像会逐渐加载。下载，解决这个问题我试图做一个预加载页面，执行以下操作：

So I have been recently developing a site, The problem is the backgrounds for each page are images, and as a result, on slower connections (which is the case of some of the target audience) the images load progressivly as they are downloaded, to resolve this I am trying to make a preloading page that does the following :

• 加载图像

• 加载完成后，将用户重定向到请求的页面

• Loads the Images

• Once the loading is done, redirects the user to the requested page

<script type="text/javascript"> <!--//--><![CDATA[//><!-- var images = new Array() var count=0; function preload() { for (i = 0; i < preload.arguments.length; i++) { images[i] = new Image() images[i].src = preload.arguments[i] } if(count==4) { window.location = "index.html"; } } preload( "backgrounds/bg1.jpg", "backgrounds/bg2.jpg", "backgrounds/bg3.jpg", "backgrounds/bg4.jpg" ) //--><!]]>

问题是它直接重定向（我假设它只是开始下载图像然后直接将一个添加到计数器变量，快速达到4并且不给图像下载时间。

The problem is it redirects directly (I assume that it just starts the download of the image then directly adds one to the counter variable, quickly reaching 4 and not giving the image the time to download.

任何想法如何让我在图像下载完成时发出信号，或者只在下载图像后执行重定向？

Any ideas how I can either make it signal me when the images have finished downloading, or only execute the redirect after it has done downloading the images ?

推荐答案

你需要等待加载事件。这很简单：

You need to wait for the load event. It's quite simple:

function preload(images, timeout, cb) { var cbFired = false, remaining = images.length, timer = null; function imageDone() { remaining--; if(remaining === 0 && !cbFired) { cbFired = true; clearTimeout(timer); cb(); } } function timerExpired() { if(cbFired) return; cbFired = true; cb(); } for(var i = 0; i < images.length; i++) { var img = new Image(); img.onload = imageDone; img.onerror = imageDone; img.src = images[i]; } timer = setTimeout(timerExpired, timeout); }

您需要检查一些内容，以免用户卡住：

You need to check a few things so that users don't get stuck:

• 你需要等待加载和错误以便在图片无法加载时页面不会卡住。
• 您应设置最大超时。
• 另外，在你的代码中， i 是一个全局变量（没有 var 声明）。

• You need to wait for both load and error so that the page doesn't get stuck if an image fails to load.
• You should set a maximum timeout.
• Also, in your code, i was a global variable (no var declaration).

以下是如何使用它：

var images = [ "backgrounds/bg1.jpg", "backgrounds/bg2.jpg", "backgrounds/bg3.jpg", "backgrounds/bg4.jpg"]; preload(images, 10000 /* 10s */, function () { window.location = 'next_page'; });