本文关于session对象方法Abandon，使用该方法可以清空session中的值。
首先阅读一下微软的文档：
Remarks
When the Abandon method is called, the current Session object is queued for deletion, but is not actually deleted until all of the script commands on the current page have been processed. This means that you can access variables stored in the Session object on the same page as the call to Abandon, but not in any subsequent Web pages.
如果调用Abandon 方法的话，在当前页面的脚本执行完之后，当前的session对象将会被删除；在本页中仍然可以调用session对象中存储的值,by