Hmm well I'm not a highly experienced coder but from what I know so far I wouldn't say thats possible at least that's what I think.
Since asp is server side when the html output is generated on the client's browser its not possible to fetch the client's browser's generated page since its the browser's engine which generates the page so what you are trying to do is catch the page generation of your asp pages on the client which I don't think is possible. But I may be wrong and hopefully someone else more experienced can point you in the right direction.