Detect click outside some elements

Question

I've been looking for some solutions to solve this problem, but nothing helps
Here is my JavaScript code

var specifiedElement = document.getElementById('a');
document.addEventListener('click', function(event) {
  var isClickInside = specifiedElement.contains(event.target);
  if (!isClickInside) {
    alert('You clicked outside A and B')
  }
});

div {
  background: #aaa;
  height:2em;
  padding: 1em;
  margin-bottom:10px;
  text-align: center;
}

<div id="a">A</div>
<div id="b">B</div>

(In JS Fiddle: https://jsfiddle.net/1zj9dmq7/)

I want when I click div a/b element, the "alert" function will not run, just running when clicked outside of that 2 elements, and without jQuery
Maybe someone can help me please, Thank You

Answer 1

Try this:

var a = document.getElementById('a');
var b = document.getElementById('b');

document.addEventListener('click', function(event) {
  var isClickInside = a.contains(event.target)||b.contains(event.target);
  if (!isClickInside) {
    alert('You clicked outside A and B')
  }
});

Demo: https://jsfiddle.net/1zj9dmq7/1/