var iframe = document.querySelectorAll("iframe"); for (var i = 0; i < iframe.length; i++) { var cur = iframe[i]; var yt = cur.className; if (cur.src.indexOf("youtube.com") != -1) { var src = cur.src; var videoId = src.match(/youtube\.com.*(\?v=|\/embed\/)(.{11})/).pop(); if (videoId.length == 11) { var thumbnailUrl = "http://img.youtube.com/vi/" + videoId + "/0.jpg"; cur.src = ""; cur.style.backgroundImage = "url('" + thumbnailUrl + "')"; cur.style.backgroundRepeat = "no-repeat"; cur.style.backgroundSize = "cover"; var link = document.createElement("a"); link.setAttribute("href", src); link.style.display = "inline-block"; link.appendChild(cur.cloneNode(true)); cur.parentNode.replaceChild(link, cur); } } }