A very basic JS calculator, built with the goal of having a very clean UI and very clean code. If you want a demo of it, you can just download it and open the HTML file
You can embed it in your website/html doc very easily with just one line:
<iframe src="./cleanCalc.html" title="cleanCalc" width="240" height="365" style="border: none;"></iframe>(replace ./cleanCalc.html with the path and name (if you renamed) where you put the HTML file, obviously)