下载图片OnClick [英] Download a picture OnClick

问题描述

当您点击图片时，如何实际下载图片？有没有一些javascript代码呢？这是我用纯HTML显示图像的方式。

How do you actually download a picture when you click on it? Is there some kind of a javascript code to do just that? Here is how i show the image with pure HTML.

<a href="#"><img src="myPic.png" border="0"></a>

推荐答案

大多数人右键点击图片，选择将图像保存为...

Most people right-click on the image and choose "Save image as..."

替代方法是链接到使用设置Content-type和Content-disposition头的服务器端脚本。在PHP中，这个例子来自文档：

The alternate is to link to use a server-side script that sets a "Content-type" and "Content-disposition" header. In PHP, that would be something like this example from the docs:

header('Content-Type: image/png'); // or 'image/jpg' or 'image/gif'
header('Content-Disposition: attachment; filename="filename.png"');
readfile('original.png');

更新：由于您说的图像是由PHP脚本生成的，首先，几个选项：

UPDATE: Since you say the image is generated by a PHP script in the first place, there are a few options:

• 将URL（sig.php？...）作为参数添加到 readfile 。这将意味着任何点击下载的人都可以进行双重处理。


• 将图像生成脚本的输出缓存到文件系统，然后将该文件传递到 readfile 。


• 编辑图像生成脚本以接受额外的参数，如 mode = download ，然后您即将输出图像，如果参数存在，设置上述两个标题。

• Put the URL (sig.php?...) as the parameter to readfile. This will mean double processing for anyone who clicks to download.
• Cache the output from your image generation script to the filesystem, then pass that file to readfile.
• Edit the image generation script to accept an extra parameter like mode=download and then where you are about to output the image, if the parameter is present, set those two headers above.

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