function write_to_logs(message) {
  window.requestFileSystem(window.PERSISTENT, 50*1024*1024, function(fs) {
    fs.root.getFile('log.txt', {create: true}, function(fileEntry) {
      // Create a FileWriter object for our FileEntry (log.txt).
      fileEntry.file(function(file) {
        fileEntry.createWriter(function(fileWriter) {
          fileWriter.onwriteend = function(e) {};
          fileWriter.onerror = function(e) {};
          fileWriter.seek(fileWriter.length); // Start write position at EOF.
          // Create a new Blob and write it to log.txt.
          var bb = new BlobBuilder(); // Note: window.WebKitBlobBuilder in Chrome 12.
          bb.append(message + 'n');
          fileWriter.write(bb.getBlob('text/plain'));
        }, errorHandler);
      }, errorHandler);
    }, errorHandler);
  }, errorHandler);
}