Hi friends! Here is my JS Calculator http://codepen.io/Parfum505/full/qNzrqb/ . I used only plain JS, so could you check it for bugs and maybe some feedback ). Thank you.
Layout and everything are nice. It seems like you’re rounding things maybe too much - it’s a little bit unintuitive to get “1 / 10,000 = 0” - but that’s not really an error.
The one thing that is off, I think, is the way that you’re using the % button. The percent button on a calculator isn’t usually used to calculate the modulus. It’s a short-hand way of adding and subtracting percents of a total (there’s a decent article here explaining how it usually works).