document.addEventListener('DOMContentLoaded', function () { // Check if the popup has been shown before if (!localStorage.getItem('youtubePopupShown')) { // Replace YOUR_VIDEO_ID with your actual YouTube video ID var youtubeURL = 'https://www.youtube.com/watch?v=77WM3ujhvJ4'; // Open the YouTube video in a new popup window var width = 560; var height = 315; var left = (screen.width / 2) - (width / 2); var top = (screen.height / 2) - (height / 2); window.open(youtubeURL, 'YouTubeVideo', `width=${width},height=${height},top=${top},left=${left}`); // Set the flag in localStorage to indicate the popup has been shown localStorage.setItem('youtubePopupShown', 'true'); } });