What are the differences between
I don’t know the differences , because when I use one or another I always get a window prompt asking me to download the file for both of them. I read the specs, but it is clueless.
This behavior depends on the browser and the file you are trying to serve. With inline, the browser will try to open the file within the browser.
For example, if you have a PDF file and Firefox/Adobe Reader, an inline disposition will open the PDF within Firefox, whereas attachment will force it to download.
If you’re serving a .ZIP file, browsers won’t be able to display it inline, so for inline and attachment dispositions, the file will be downloaded.