js to achieve the pop-up effect

<!-- Popup layer -->
<div id="popLayer"></div> <!--Black mask-->
<div id="popBox">
  <div class="close">
   X
  </div>
  <div>
   <!-- Contents -->
 </div>
</div>

//Click the close button var close = document.querySelector(".close")
close.onclick = function () {
 console.log("click")
 var popBox = document.getElementById("popBox");
 var popLayer = document.getElementById("popLayer");
 popBox.style.display = "none";
 popLayer.style.display = "none";
}


//Call when display is neededvar popLayer = document.getElementById("popLayer");
popBox.style.display = "block";
popLayer.style.display = "block";

/* Popup layer*/
#popLayer {
 display: none;
 background-color: #000;
 position: absolute;
 top: 0;
 right: 0;
 bottom: 0;
 left: 0;
 z-index: 10;
 opacity: 0.6;
}

/*Popup layer*/
#popBox {
 display: none;
 background-color: #FFFFFF;
 z-index: 11;
 width: 220px;
 height: 300px;
 position: fixed;
 top: 0;
 right: 0;
 left: 0;
 bottom: 0;
 margin: auto;
}

/*Close button*/
#popBox .close {
 width: 20px;
 height: 20px;
 border-radius: 50%;
 position: absolute;
 border: 1px solid #fff;
 color: #fff;
 text-align: center;
 line-height: 20px;
 right: 8px;
 top: 8px;
 z-index: 50;
}

#popBox .close a {
 text-decoration: none;
 color: #2D2C3B;
}