Uncaught TypeError: Cannot read properties of null (reading 'addEventListener') at testapp.js:12:10

I linked my HTML page to the next one. but once I click 'Submit' button it gives me an error "Uncaught TypeError: Cannot read properties of null (reading 'addEventListener') at testapp.js:12:10" if I click submit button it will go to the next page but my calculation is not showing on the console if I Commented on the 'onclick' button my calculation is showing on the console but both Button Click and go to next page and calculation does not working at the same time