• Not supported in Firefox
• Supported in Chrome
• Not supported in Safari
• Not supported in IE
• Not supported in Opera

Chrome has induce a new DownloadURL type for the drag and drop method setData. This allows you to drag a file from a webpage to the desktop.

Using a Chrome browser drag this link to desktop > Drag this

Object detection

The object detection is not very clean at the moment, but this example from box.net article seems to work.

this.addEventListener("dragstart", function(e) {
    if (e.dataTransfer && e.dataTransfer.constructor == Clipboard &&
        e.dataTransfer.setData('DownloadURL', 'http://example.org')) {
            e.dataTransfer.setData("DownloadURL", url);
    }
},false);