Measure-it

Measure-it is a simple tool that allows you to scale any element from a webpage. Firefox, as a browser, offers you a lot of tools with different features, but this extension, although basic, could be something special for certain types of people that require something to assist them in their projects.

By drawing a ruler across any page you can check, in pixels, the width, height and the alignment of the page elements. It activates with a simple use of the keyboard shortcut Alt+Shift+M.

After you enable it, the whole page will become a bit dimmer and when you start to trace your element the shape of the ruler will appear on the screen, letting you determine the measurements of your chosen elements.

Sometimes, it might be harder to accurately select an element on the page, and you cannot modify or change the location of the measurement overlay either. If you click somewhere, the overlay will just disappear.

Not a lot of people are in need of such a tool in their daily work, but for those who operate in the web development field, for example, it is a very welcomed addition, as there are not many plugins that can do this.

The extension is pretty handy when it comes to scaling static UI elements and different frontend components of a website page, and it also works with other web extensions.

Measure-it has a few basic options that you can meddle with to set them after your preference. Things like the overlay and the popup shape color, the background opacity and also the keyboard shortcut that activates the ruler can all be set as you like.

Just grab this addon if you want to measure. And yes, you can hit the ESC key and the measurement window just goes away. That is a must for some!