spec/fixtures/pages/onkeyup.html (9 lines of code) (raw):
<html>
<body>
<script type="text/javascript" charset="utf-8">
document.onkeyup = function(e) {
require('electron').ipcRenderer.sendToHost('keyup', e.key, e.code, e.keyCode, e.shiftKey, e.ctrlKey);
}
</script>
</body>
</html>