I want to be able to listen to step UP (increment) and step down events with jQuery. (currently I can only understand how to lis
I'm not sure if there is a listener of the stepUp and StepDown but you can externalize the PLUS and LESS buttons of the input number using:
document.getElementById("myNumber").stepUp(5); //increase the value +5
document.getElementById("myNumber").stepDown(5); // decrease the value -5
So you can finally achieve your objective!
Reference: https://www.w3schools.com/jsref/met_number_stepup.asp
NOTE: Be aware that IE11 and EDGE doesn't implement stepUp / stepDown. On my case I just remove the + and - icon and leave only the input number field. Hope EDGE die soon...