Chrome extension download file example

Some example of generating file from chrome extension.

logError: function(error) { console.log(error); }
downloadFile: function(format, file_name, data){
    if(!format){
      format = 'txt';
    }
    if(!file_name){
      file_name = 'default';
    }
    file_name = file_name + '.' + format;
    if(data.length == 0){
      return; // stupid stub
    }
    window.requestFileSystem = window.requestFileSystem || window.webkitRequestFileSystem;
    window.requestFileSystem(window.TEMPORARY, 1024*1024, function(fs) {
      fs.root.getFile(file_name, {create: true}, function(fileEntry) {
        fileEntry.createWriter(function(fileWriter) {
          var blob = new Blob([data]);
          fileWriter.addEventListener("writeend", function() {
            chrome.tabs.create({ url: fileEntry.toURL() });
          }, false);
          fileWriter.write(blob);
        }, logError);
      }, logError);
    }, logError);
  },