Feedback on my Calculator, please

Hey! Just finished my javascript calculator and submited it.

I would like general opinions and on specific points would be great too.

Some aspects about this proj.:

  1. The JS is a mess, in my opinion. And I know, nothing is commented yet,. Sorry about that.
    I would like tips to simplify it and make a better code.

  2. I fixed every bug I found. If you subtract 2 from 2.4, the result will be 0.4, not 0,3999999… (thank goodness). So, you canc test all the way to help me find more errors. I would appreciate.

  3. I would like some hints to test this and other projects. I don’t know how to do it exactly yet.

I’ll add in the future some details like the possiblity of using keyboard and the +/- (sign change) button
Thank you guys in advance!

1 / 7 * 7 should be 1 and not 1.000000001

1 / 3 * 3 should be 1 and not 0.999999999

Thank you for your reply!

In this calculator, 1 / 3 is 0.333333333 (precisely 9 places after decimal point.),
not 0.333… (infinite 3s after decimal point).

So, doing back 0,33333 x 3 will be 0,999999999.

I don’t know yet how to fix it, because searched it previously and didn’t found an answer.
So, for some calculations, the calculator will always give the approximate value for now.

I’ll do some research again to see if I can find something.