JS calculator: one minor bug need help

Hi please see my JS calculator codepen and let me know what you think? Its simple but does the trick . I used both vanilla JS and Jquery to try to get a feel of both. Criticisms are welcome.

I have one issue with my calculator app though. Its not required for the project, but I am trying to make event clicker function in jquery when click enter it is same as using “=” button on the calculator.

Its working as it should - however as soon as it does then it refreshes the page. How can I fix this? As I understand this maybe because the button is child element of a form element if I’m not mistaken. ??
But if I want to keep it as so how can I workaround this using JS or Jquery.
Thanks Alot!