Can javascript access a filesystem? [duplicate]

Tiddlywiki has several methods of saving data, depending on which browser is used. As you could see in the source.

• If ActiveX is enabled, it uses Scripting.FileSystemObject.
• On Gecko-based browsers, it tries to use UniversalXPConnect.
• If Java is enabled, it uses the TiddlySaver Java applet.
• If Java LiveConnect is enabled, it tries to use Java's file classes.

HTML5's File[1], FileWriter[2], and FileSystem[3] APIs are available in the latest Developer channel of Google Chrome. The FileSystem API lets you read/write to a sandbox filesystem within a space the browser knows about. You cannot, for example, open 'My Pictures' folder on the user's local FS and read/write to that. That's something in the works, but it won't be ready for a while. Example of writing a file:

window.requestFileSystem(  TEMPORARY,        // persistent vs. temporary storage  1024 * 1024,      // 1MB. Size (bytes) of needed space  initFs,           // success callback  opt_errorHandler  // opt. error callback, denial of access);function initFs(fs) {  fs.root.getFile('logFile.txt', {create: true}, function(fileEntry) {    fileEntry.createWriter(function(writer) {  // FileWriter      writer.onwrite = function(e) {        console.log('Write completed.');      };      writer.onerror = function(e) {        console.log('Write failed: ' + e.toString());      };      var bb = new BlobBuilder();      bb.append('Lorem ipsum');      writer.write(bb.getBlob('text/plain'));    }, errorHandler);  }}

Check out this HTML5 Storage slide deck for more code snippets.

It uses a java file references like this:

drivers.tiddlySaver = {        name: "tiddlySaver",        deferredInit: function() {            if(!document.applets["TiddlySaver"] && !$.browser.mozilla && !$.browser.msie && document.location.toString().substr(0,5) == "file:") {                $(document.body).append("<applet style='position:absolute;left:-1px' name='TiddlySaver' code='TiddlySaver.class' archive='TiddlySaver.jar' width='1'height='1'></applet>");            }        },        isAvailable: function() {            return !!document.applets["TiddlySaver"];        },        loadFile: function(filePath) {            var r;            try {                if(document.applets["TiddlySaver"]) {                    r = document.applets["TiddlySaver"].loadFile(javaUrlToFilename(filePath),"UTF-8");                    return (r === undefined || r === null) ? null : String(r);                }            } catch(ex) {            }            return null;        },        saveFile: function(filePath,content) {            try {                if(document.applets["TiddlySaver"])                    return document.applets["TiddlySaver"].saveFile(javaUrlToFilename(filePath),"UTF-8",content);            } catch(ex) {            }            return null;        }    }