Can you also add the option to count the same numbers if we select any text on screen, and then show them in menu or popup if we select the text and right click on it?
Thanks for the suggestion. It sounds interesting to hear. I will try to add this feature in my free time.
I am also using dark theme in my browser and I can't see any text because background is very similar color like text.
I guess I could just manually change the colors in code if you tell me exact location, but it would be better to have the option to select alternative light or dark text.
Yes of course you can. You just need to change the following two line from the script.
counter.style.color = '#333';
counter.style.color = 'gray';
And what you will write after finding them out.
counter.style.color = 'red';
counter.style.color = 'red';
You can add the color you want here if you want. You can put blue in place of red if you want. If the color name does not change, just google it and find out the hex code of that color.