Answers for "add multiple event listener to a button"

add event listener to multiple element in JS

document.querySelectorAll('.some-class').forEach(item => {
  item.addEventListener('click', event => {
    //handle click
  })
})

Add event listener to multiple buttons with the same class

btns = document.getElementsByClassName("saveBtn");
    for (var i = 0; i < btns.length; i++) {
        btns[i].addEventListener("click", function () {
			//Add function here
        });
    }