document.addEventListener('click', function (event) {

	// Игнорируем клики, которые не относятся к нашей кнопке
	if (!event.target.hasAttribute('data-fullscreen')) return;

	// Если уже в полном, выйти
	// Иначе, снова открыть полный экран
	if (document.fullscreenElement) {
		document.exitFullscreen();
	} else {
		document.documentElement.requestFullscreen();
	}

}, false);

d=document.querySelector("#bg");
d.onclick = function(e) {
  if (e.target !== this)
    return;
 alert("click")
}

const comments = {"reviews": [
        {
            "id": 1,
            "children": [
                {
                    "id": 2,
                    "children": [
                        {
                            "id": 3,
                            "children": [
                                {
                                    "id": 4,
                                    "children": [],
                                    "user": {
                                        "id": 1,
                                        "username": "Admin",
                                        "avatar": "http://127.0.0.1:8000/media/developers/default.jpg"
                                    },
                                    "text": "Ch - 3",
                                    "uploaded_time": "2020-07-30T12:24:52.414582+03:00",
                                    "parent": 3
                                }
                            ],
                            "user": {
                                "id": 1,
                                "username": "Admin",
                                "avatar": "http://127.0.0.1:8000/media/developers/default.jpg"
                            },
                            "text": "Ch - 2",
                            "uploaded_time": "2020-07-28T18:20:39.887167+03:00",
                            "parent": 2
                        }
                    ],
                    "user": {
                        "id": 1,
                        "username": "Admin",
                        "avatar": "http://127.0.0.1:8000/media/developers/default.jpg"
                    },
                    "text": "Ch - 1",
                    "uploaded_time": "2020-07-28T18:20:21.004694+03:00",
                    "parent": 1
                }
            ],
            "user": {
                "id": 1,
                "username": "Admin",
                "avatar": "http://127.0.0.1:8000/media/developers/default.jpg"
            },
            "text": "Text",
            "uploaded_time": "2020-07-28T18:19:22.644345+03:00",
            "parent": null
        }
    ],}

  function countComments(obj){
    let total = 0;
    count(obj);
    function count(obj){
        for(let i in obj){
        if(obj[i].hasOwnProperty('children')){
            count(obj[i].children);
        }
        total++;
     } 
      }
      return total;
      
  }
let total = countComments(comments.reviews);
console.log('Всего комментов: '+ total);