button

by tek

HTML

<button id="btn" type="button">
	button
</button>

JavaScript

const fnFactory = function() {
  let flg = true;

	const fn = function () {
		flg = !flg;
		alert(flg);
	}
  
  return fn;
}
    
const fn = fnFactory(); 

const btn = document.getElementById('btn');
btn.addEventListener('click', function() {
  fn();
});