当Ajax调用调用时，PHP触发下载不起作用

Question

I built a small PHP script which creates an Excel spreadsheet and forces its download, by defining the corresponding header. When I call this script directly by its URL (or even through JS with window.location.replace), everything works fine. Now, when I call the same script via an Ajax call (both synchronously and asynchronously) nothing happens.

Can somebody explain this behavior?

Regards Sebastian

Answer 1

AJAX requests are processed in the background, so the download headers will be ignored and only passed to your callback.

If you want to force download the file without redirecting him to the page you can

• inject an iframe to the page and pass the download url as src-parameter
• link to the download url with an a-tag and add the HTML5 download-attribute to it
• put the result of your ajax-request base64-encoded in an injected a-tag as src parameter and pass a download-parameter.

Example for downloading the url https://stackoverflow.com/ as "stackoverflow.html": <a href="https://stackoverflow.com/" download="stackoverflow.html">Click me!</a>

Example for downloading the text "test" as "file.txt": <a href="data:text/plain;base64,dGVzdA==" download="file.txt">Click me</a> (where dGVzdA== is "test" base64-encoded)

After injecting both a-tags you can use e.g. jQuery to simulate an user clicking on them.