<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=Edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Loading Page Sample</title>
</head>
<body>
<div class="loading-page">
<style>
/* styles for loading page */
html, body {
background-color: #f5f5f5;
width: 100%;
height : 100%;
overflow: hidden;
position: relative;;
box-sizing: border-box;
font-family:Helvetica,Arial,sans-serif;
color: #272727;
}
.loading-page {
position: absolute;
width: 500px;
height: 300px;
padding: 0;
top: 50%;
left: 50%;
text-align: center;
margin: -150px 0 0 -250px;
}
.loading-page h1, .loading-page h2 {
margin: 0;
padding:0;
font-weight: 300;
line-height: 30px;
color: #272727;
}
.loading-page h1{
font-size: 30px;
margin-bottom:20px;
}
.loading-page h2 {
font-size: 20px;
}
</style>
<h1>Sample App</h1>
<h2>Glorious things are waiting for you. We're just getting them ready...</h2>
<script>
!function(){function e(){this.element=function(e){return e(i.contentWindow.document.querySelector(".loading-page")),this}.bind(this),this.doneLoading=function(){delete window.loadingPage,this.element(function(e){e.classList.add("fade-out")}),setTimeout(function(){document.body.removeChild(i),document.body.classList.add("loaded")},250)}}var t=document.querySelector(".loading-page script");t.parentNode.removeChild(t);var n=document.querySelector(".loading-page"),o='<!DOCTYPE html><html lang="en"><head> <meta charset="utf-8"> <meta http-equiv="X-UA-Compatible" content="IE=Edge"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <style> @keyframes loadingPageFadeOut { 0% { opacity: 1; } 100% { opacity: 0; } } .loading-page.fade-out { animation-name: loadingPageFadeOut; animation-duration: .25s; transition-timing-function: ease-out; opacity: 0; animation-fill-mode: both; } </style></head><body>{{iframe-inner-html}}</body></html>';o=o.replace("{{iframe-inner-html}}",n.outerHTML);var i=document.createElement("iframe");i.setAttribute("style","position:fixed; top:0px; left:0px; bottom:0px; right:0px; width:100%; height:100%; border:none; margin:0; padding:0; overflow:hidden; z-index:999999;"),document.body.appendChild(i),i.contentWindow.document.open(),i.contentWindow.document.write(o),i.contentWindow.document.close(),n.parentNode.removeChild(n),window.loadingPage=new e}();
</script>
</div>
<script>
// pretending to load my app scripts, data, and build the DOM
setTimeout(function(){
var el = document.createElement('h1');
el.innerHTML = 'Hello from My App';
document.body.appendChild(el);
window.loadingPage.doneLoading();
}, 1000)
</script>
</body>
</html>