<!DOCTYPE html>
<html>
<body>
<script type="text/javascript">
var nav, win;
function openWindow() {
return new Promise(resolve => {
win = window.open(window.location);
win.addEventListener("load", function listener() {
nav = win.navigator;
resolve();
}, false);
});
}
function navigate() {
win.location = "http://example.com/";
}
function check() {
return "mozAddonManager" in nav;
}
</script>
</body>
</html>