How can I intercept the post data a page is sending in FF or Chrome via configuration, extension or code? (Code part makes this programming related. ;)
I currently use Wireshark/Ethereal for this, but it's a bit difficult to use.
You could just use the Chrome Developer Tools, if you only need to track requests. Activate them with Ctrl+Shift+I and select the Network tab.
This works also when Chrome talks HTTPS with another server (and unless you have the HTTPS private key you cannot use Wireshark to sniff that traffic).
(I copied this answer from this related query.)