firebugfirefoxredirection
In Firebug, how can I stop a redirect? I want to examine and edit a webpage before it redirects. Under the Net tab, using Persist I can see all the GET including the previous pages and the redirect page, but I am still taken to the final redirect page. I want to stop one move before this. Is it possible?
EDIT: It is a JavaScript based redirect, but I need the rest of the JavaScript working, so blocking all JavaScript from execution is not a solution in this instance.
I realize this is far from a perfect answer, as this will only work for responses that serve up content, but I decided to post it as there are currently zero useful, actionable answers.
As a quick-and-dirty solution you may be able to use the debugger (accessible by F12 or CTRL+SHIFT+I in most browsers) to give your self an opportunity to opt out of a redirect.
Run this line in the console before the page runs any scripts of its own:
window.onbeforeunload = function(){ return 'Leave page?'; };
For example, using Chrome:
F12) and switch to the Sources tab.F8 to put the debugger into step-through mode.F8 again to allow scripts to run and let the page finish loading.
Best Answer
What kind of redirect? There are Firefox addons outside of Firebug you can use to stop redirects. Firebug does not seem to provide this functionality itself.
Redirects based on the HTML "Meta refresh" (also HTTP "Refresh") can be blocked by setting accessibility.blockautorefresh to true in about:config. In fact, this corresponds to the "Warn me when web sites try to redirect or reload the page" option in Options > Advanced > General. Alternatively, addons such as RefreshBlocker can be used.
For JavaScript based redirects, JS can be completely disabled or addons such as NoScript can be used.
There generally isn't much you can inspect on a page that is redirected using HTTP 3xx response codes. In case anyone wants to know, setting network.http.redirection-limit to 0 in about:config causes all of these to show a Firefox error page.
JS redirects
JS-based redirects are difficult. I'm not aware of a method to stop them from within the browser. However, you can intercept the responses with a debugging proxy like Fiddler2, and replace it with your own modified response (the AutoResponder in Fiddler2 is one way). In this modified response, you'd want to remove any references to
window.locationandlocation, the usual ways to change the page from JS [you might be able to get away with replacing them with a dummy variable, e.g.var thisIsAMadeUpVarName]. That way, the redirect would never get to the browser. See the "Search and replace in HTML." section of this document (you may wish to also filter JS files if they are served separately).