BeforeNavigate2获取下一个URL

BeforeNavigate2(const pDisp: IDispatch; var URL: OleVariant; var Flags: OleVariant;
                              var TargetFrameName: OleVariant; var PostData: OleVariant;
                              var Headers: OleVariant; var Cancel: WordBool);begin
     ShowMessage(Vartostr(URL));
end如果我打开百度了，然后输入新浪的URL，回车，首先会弹出http://www.baidu.com/，然后才弹出http://www.sina.com.cn，请问怎么在弹出http://www.baidu.com/的时候知道下一个将弹出的URL是http://www.sina.com.cn呢