jHeartbeat 是一个jQuery 的插件，用来定时执行某项任务，例如定时向服务器发送请求；定时更新页面元素等等，特别适合用在聊天室开发上。-JHeartbeat is a jQuery plug-in for the timing of the implementation of a task, such as the time to send a request to the server regularly update page elements, and so on, espe