如何使用javascript每5秒重新加载img？ [英] How to reload img every 5 second using javascript?

问题描述

如何使用javascript每5秒重新加载一次img？

How to reload img every 5 second using javascript ?

<img src="screen.jpg" alt="" />

推荐答案

每次要重新加载图像时，都必须像这样更改图像URL：screen.jpg？rand = 123456789，其中123456789是随机生成的数字，每次要重新加载图像时都会重新生成。浏览器会认为它是一个不同的图像，并实际下载它，而不是从缓存中检索它。 Web服务器很可能会忽略并丢弃问号后的所有内容。

Every time you want to reload the image, you must change the image url like so: "screen.jpg?rand=123456789" where "123456789" is a randomly generated number, which is regenerated every time you want to reload the image. The browser will think that it is a different image, and actually download it again, instead of retrieve it from the cache. The web server will most likely ignore and discard everything after the question mark.

要首先重新加载，您必须使用Javascript来获取图像元素并改变来源。我能看到的最简单的选择是给image元素一个 id 属性，如下所示：

To cause the reload in the first place, your would have to use Javascript to get the image element and change the source. The easiest option I can see is to give the image element an id attribute, like so:

<img src="screen.jpg" id="myImage" />

然后你可以改变图像的来源：

Then you may change the source of the image:

var myImageElement = document.getElementById('myImage');
myImageElement.src = 'screen.jpg?rand=' + Math.random();

要在设定的计时器上执行此操作，请使用顶级Javascript函数 setInterval ：

To do this on a set timer, then use the top-level Javascript function setInterval:

setInterval(function() {
    var myImageElement = document.getElementById('myImage');
    myImageElement.src = 'screen.jpg?rand=' + Math.random();
}, 5000);

第二个参数指定5000毫秒，相当于5秒。

The second argument specifies 5000 milliseconds, which equates to 5 seconds.

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