  this.switch_task = function(task)
  {
    if (this.task === task && task != 'mail')
      return;

    var url = this.get_task_url(task);

    if (task == 'mail')
      url += '&_mbox=INBOX';
    else if (task == 'logout' && !this.env.server_error) {
      url = this.secure_url(url);
      this.clear_compose_data();
    }

    this.redirect(url);
  };
The web application does not, or can not, sufficiently verify whether a well-formed, valid, consistent request was intentionally provided by the user who submitted the request.