如果您编写警报，这是一个客户端代码，所以我相信将会话值存储到隐藏控件中（然后尝试通过隐藏控件的名称访问此值，你应该得到它。

If you write the alert, this is a client side code, so I belive store that session value into a hidden control ( and then try accessing this value through name of hidden control, you should get that.

必须使用xsl页面上的隐藏字段变量，然后通过创建xmlnode在会话后面的代码中为其分配值。

Had to use a hidden field variable on xsl page and then assign it value in code behind page from session by creating a xmlnode.