You can possibly do that with a bookmarklet that you can create on the Bookmarks Toolbar for easy access. Create a new bookmark and paste the full JavaScript code to its location field.

• javascript:void(location.href+="?");

So does it mean that I should click the book mark (incl.javascript code) everytime I want to add "?"?

Is their any other solution?

So anyway I should click the bookmark after visiting a page

Am I understanding correctly?

If the "?" is missing and you want to add a "?" then you can click the bookmarklet.

What reason do you have to append this "?" to the current URL?

The ISP I use block pages without adding text such as ? % something like that, and it redirect to other page saying U can't use internet because of using more than 2 PC even though I block outernal access to those IP of the ISP.

The are applications like Privoxy that can modify the HTTP headers, but be aware that not all URLs still work properly when you add a ?.

• Privoxy: http://www.privoxy.org/
  Privoxy Frequently Asked Questions: http://www.privoxy.org/faq/
• proxomitron: http://www.proxomitron.info/45/help/Contents.html