<head>
<style>
@font-face {
    font-family: 'FontAwesome';
    src: url("font1.woff2") format("woff2");
    font-weight: normal;
    font-style: normal
}

.foobar {
    font: normal normal normal 14px / 1 FontAwesome;
}
</style>
</head>
<body>foobar<script>document.body.offsetHeight</script>
<script async="true" src="foobar.js"></script>