FileSaver.js

FileSaver.js implements the HTML5 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.

Looking for canvas.toBlob() for saving canvases? Check out canvas-toBlob.js for a cross-browser implementation.

Supported Browsers

Browser	Constructs as	Filenames	Max Blob Size	Dependencies
Firefox 20+	Blob	Yes	800 MiB	None
Firefox < 20	data: URI	No	n/a	Blob.js
Chrome	Blob	Yes	345 MiB	None
Chrome for Android	Blob	Yes	?	None
IE 10+	Blob	Yes	600 MiB	None
Opera 15+	Blob	Yes	345 MiB	None
Opera < 15	data: URI	No	n/a	Blob.js
Safari 6.1+*	Blob	No	?	None
Safari < 6	data: URI	No	n/a	Blob.js

Feature detection is possible:

try {
    var isFileSaverSupported = !!new Blob;
} catch (e) {}

IE < 10

It is possible to save HTML documents (and only HTML documents) in IE < 10 without Flash-based polyfills. See sudodoki's comment for more information on how to accomplish this.

Safari 6.1+

Blobs may be opened instead of saved sometimes—you may have to direct your Safari users to manually press ⌘+S to save the file after it is opened. Using the application/octet-stream MIME type to force downloads can cause issues in Safari.

Syntax

FileSaver saveAs(in Blob data, in DOMString filename)

Examples

Saving text

var blob = new Blob(["Hello, world!"], {type: "text/plain;charset=utf-8"});
saveAs(blob, "hello world.txt");

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

Saving a canvas

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() that polyfills this.