I got a custom HTTP-500 error site from here. (codepen).
In the browser, this works as intended, at least when I'm watching the site at codepen.
When I copy the files to my IIS however, I get the error-message:
Uncaught TypeError: Cannot read property 'children' of null
Most basic example to reproduce on my machine is this:
<!Doctype HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>ASP 500 Error</title>
<link rel="stylesheet" type="text/css" href="/error/style.css" />
<script src="/error/error500.js"></script>
</head>
<body>
<div class="stack-container">
<div class="card-container">
<div class="perspec" style="--spreaddist: 125px; --scaledist: .75; --vertdist: -25px;">
<div class="card">
<div class="writing">
<div class="topbar">
<div class="red"></div>
<div class="yellow"></div>
<div class="green"></div>
</div>
<div class="code">
<ul>
</ul>
</div>
</div>
</div>
</div>
</div>
</div>
</body>
</html>
Tested in IE and Chrome. Both work on codepen, neither does it locally.
I checked the references to the JS/CSS already and they work. On top of that, I tried to figure out if there are any 3rd party libs involved on codepens site, but it doesn't seem like it.