Can javascript access a filesystem? [duplicate]

Solution 1:

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.

Solution 2:

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.