stereo.html
<!DOCTYPE html>
<html><head></head>
<body>
<script>
newWindow = window.open('mono.html');
newWindow.addEventListener('load', function() {
var el = newWindow.document.getElementById('p26');
if(el) el.click();
}, false);
</script>
</body>
</html>
mono.html
<!DOCTYPE html>
<html><head></head>
<body>
<a id="p26" href="#" onclick="alert('yes!'); return false">yes?</a>
</body>
</html>