It is easy to use too many font sizes on a website.
Especially when using em font sizes as these are relative to their parent.

I wanted an easy way to see the number of font sizes used on a website.
I created this JavaScript bookmarklet.

Hide/Show inline font sizes with the action in the bottom right

To use:
1. Add a new bookmark in your browser
2. Paste the below code into the URL
3. Go to a website and click the bookmark link