FileSaver.js implements the W3C saveAs() FileSaver interface in browsers that do not natively support it. There is a FileSaver.js demo that demonstrates saving various media types.

FileSaver.js is the solution to saving files on the client side, and is perfect for webapps that need to generate files or for saving sensitive information that shouldn't be sent to an external server.

• Internet Explorer 10+
• Firefox 4+
• Google Chrome
• Opera 11+
• Safari 5+

Unlisted versions of browsers (e.g. Firefox 3.6) will probably work too; I just haven't tested them.

FileSaver saveAs(in Blob data, in DOMString filename)

var bb = new BlobBuilder;
bb.append("Hello, world!");
saveAs(bb.getBlob("text/plain;charset=utf-8"), "hello world.txt");

The standard W3C File API BlobBuilder interface is not available in all browsers. BlobBuilder.js is a cross-browser BlobBuilder implementation that solves this.

var canvas = document.getElementById("my-canvas"), ctx = canvas.getContext("2d");
// draw to canvas...
canvas.toBlob(function(blob) {
    saveAs(blob, "pretty image.png");
});

Note: The standard HTML5 canvas.toBlob() method is not available in all browsers. canvas-toBlob.js is a cross-browser canvas.toBlob() implementation that solves this.

var filesaver = saveAs(blob, "secret stuff that you won't send to a server.truecrypt");
filesaver.onwriteend = function() {
	// file saved, do something here
};

Note that Internet Explorer cannot abort saves, so

var filesaver = saveAs(blob, "whatever");
cancel_button.addEventListener("click", function() {
    if (filesaver.abort) {
        filesaver.abort();
    }
}, false);

This isn't that useful unless you're saving very large files (e.g. generated video).