How to do: when you click on the button, show the block, when you click again, hide (on pure js)?

Question

css

How to do: when you click on the button, show the block, when you click again, hide (on pure js)?
https://codepen.io/anon/pen/vrddEK

Answer 1

var popup = document.querySelector('.popup');
var open = document.querySelector('.open');
popup.style.display = 'none'


open.addEventListener("click",      function() {

    if(popup.style.display == 'none')  popup.style.display = 'block';
    else popup.style.display = 'none'
    
  });