javascript捕获和篡改http请求

Question

Is there a way with javascript on a page to tamper http requests done by other scripts (on same page)? The other scripts can be from external domains.

Let's say on a page X a script loaded from an external domain performs an http get like GET http://www.example.com?foo=bar is it possible that a previously loaded script in the same page X can capture this request, and tamper with it so it becomes GET http://www.example.com?foo=qux ?

In jquery i can achieve this by wrapping the ajax get post methods. But is this possible for plain javascript, no frameworks, working across all page and client's http requests?

It seems to me that for this to be done, the script must be able to override something very deep in the core. If i have to guess i would say it's not possible by design and because of security . What do you think?

ps no proxies, no external tools.

Answer 1

No you can't capture the HTTP request going out of your app, once it has gone out of your app .

However, there is one work around possible

1. if you want to alter some parameters before it goes of your app ,
2. All the other request from your website are AJAX requests
3. They are invoking your custom method, say customAjax() which can alter the parameters of the actual request that will go out.