HTML Window top Property

The HTML Window top property returns the topmost browser window of the current window.


Following is the syntax −

Let us see an example of HTML Window top Property −


 Live Demo

<!DOCTYPE html>
   body {
      color: #000;
      height: 100vh;
      background-color: #8BC6EC;
      background-image: linear-gradient(135deg, #8BC6EC 0%, #9599E2 100%) no-repeat;
      text-align: center;
   .btn {
      background: #db133a;
      border: none;
      height: 2rem;
      border-radius: 2px;
      width: 30%;
      display: block;
      color: #fff;
      outline: none;
      cursor: pointer;
      margin: 1rem auto;
<h1>HTML Window top Property Demo</h1>
<button onclick="create()" class="btn">Check current window is topmost</button>
<div class="show"></div>
   function create(){
      if( === window.self){
         document.querySelector('.show').innerHTML='The current window is the topmost window';
      } else{
         document.querySelector('.show').innerHTML='The current window is not the topmost window';


Click on “Check current window is topmost” button to check if the current window is the topmost window or not: