how to set content-disposition = attachment via javascript?

Question

How can I set content-disposition = attachment via javascript?

Basically, I would like to force a "SaveAs" operation after a page has loaded via Javascript, using Firefox.

How can I do this ?

Answer 1

Content-Disposition is a response header, ie. the server must return it. You can't achieve this with client-side javascript.

Answer 2

Firefox and Chromium-based browsers support the download attribute. If you need better compatibility now, use the Flash-based Downloadify as a fallback.

---

HTML only: use the download attribute:

<a download href="http://upload.wikimedia.org/wikipedia/commons/b/bb/Wikipedia_wordmark.svg">Download</a>

---

Javascript only: you can save any file with this code:

function saveAs(uri) {
    var link = document.createElement('a');
    if (typeof link.download === 'string') {
        link.href = uri;
        link.setAttribute('download', true);

        //Firefox requires the link to be in the body
        document.body.appendChild(link);

        //simulate click
        link.click();

        //remove the link when done
        document.body.removeChild(link);
    } else {
        window.open(uri);
    }
}

var file = 'http://upload.wikimedia.org/wikipedia/commons/b/bb/Wikipedia_wordmark.svg';
saveAs(file);