Some Word type programs have that. Firefox does not.

You might find something here; Go to the Mozilla Add-ons Web Page {web Link} (There’s a lot of good stuff here) and search for what you want.

Hi joifre,

On this page you will find the only three ruler add-ons  :

https://addons.mozilla.org/en-US/firefox/tag/ruler

You may also find this article interesting :

https://developer.mozilla.org/en-US/docs/Tools/Rulers

Murphy the third one looks like what I want. Twice I've clicked it, then install-restart but it doesn't restart, I restarted it (winkey-u-r) but when it restarted, I opened Firefox but couldn't see the ruler.

Did you enable this Ruler feature in the developer toolbox settings?

• https://developer.mozilla.org/en/Tools/Tools_Toolbox#Settings

If you open the developer toolbox and enable this feature and click the Ruler ruler icon on the toolbar and this should work immediately.

On mine theres no graphics like that. I did press shift + i but only got bookmarks. I don't iknow if it went on in the firsr place as it didn't restart when I pressed the button.

Did you look at the Web Developer menu?

• "3-bar" menu button or Tools -> Web Developer

I usually have the Developer Toolbar enabled (Shift+F2) for quick and easy access to the developer tools.