<!DOCTYPE html>
<html style="width: 1px">
<head>
<script>
function boom()
{
document.documentElement.offsetHeight;
var x = document.getElementById("x").firstChild;
x.data = "a" + x.data;
}
</script>
</head>
<body onload="boom();"><span id="x">
‪𐡱</span></body>
</html>