<!DOCTYPE html>
<html>
<head>
<meta charset="utf8">
<style>
@counter-style triangle { symbols: a; }
@counter-style disc { system: extends triangle; }
</style>
<script>
function crash() {
var styleNode = document.createElement("style");
styleNode.textContent =
"@counter-style triangle { symbols: b; } " +
"@counter-style disc { system: extends triangle; } " +
"ul {}";
document.getElementsByTagName("head")[0].appendChild(styleNode);
}
</script>
</head>
<body onload="crash()">
<ul><li>Don't technically need any text here, but here's some anyway.