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.

Feature detection is possible:

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

saveTextAs() will help you to save HTML documents or text file in IE < 10 without Flash-based polyfills. However, only text based files could be saved in IE < 10, that means canvas will not be supported.

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. Further information is available on the issue tracker.

Save Text File:

boolean saveTextAs(in textContent, in fileName, in charset)

Save File(HTML 5):

FileSaver saveAs(in Blob data, in DOMString filename)

saveTextAs("Hi,This,is,a,CSV,File", "test.csv");
saveTextAs("<div>Hello, world!</div>", "test.html");

For IE < 10, available file extensions are ".htm/.html/.txt", any other text based file will be appended with ".txt" file extension automatically. For example, "test.csv" will be saved as "test_csv.txt".

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.

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.