说明：  JavaScript倒计时代码:新建一个文本文件(后缀名是TXT)，然后将下面的源代码全部复制／粘贴到这个文本文件中，保存后改变这个文本文件的后缀名为HTML，然后在IE浏览器中打开并运行。考虑到onTimer函数中执行语句的延迟，实际中你可以减少elapse的值，使得倒计数秒更为精确！欢迎大家指点!
(countdown JavaScript code : a new text file (suffix were TXT), Below then all of the source code copy/paste text of this document, preserved change the text of the document known as HTML suffixes, and then the IE browser to open and run. OnTimer function to consider the implementation of the delayed statements, you can actually reduce the value elapse, make more precise countdown seconds! We welcome the guidance!)