Javascript Injection problems

I'm trying to use the javascript injection markupjavascript:alert(document.cookie); on the URL bar but nothing shows up when I press enter. it just moves the cursor back to where it was before i clicked the URL bar.

I'm using the latest version of Firefox (17.0.1) and javascript is enabled on it. any ideas how to fix this?

Firefox disabled the ability to execute Javascript in the URL, but you can still use it in the developer/web console. The add-on Firebug would probably be worth your time.

Like I've stated in the past, If you save your injection as a bookmark, They will execute just fine in firefox.

Or just use scratchpad, which is a javascript console that will run javascript on the tab you are on. thats what I use.