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.:

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.  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.
 I would like some hints to test this and other projects. I don’t know how to do it exactly yet.
Thank you guys in advance!