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