<!doctype html>
<html>
<head>
<style>
a {
    color: red;
}

a:hover {
    color: green;
}

b {
    border: 3px solid currentColor;
}
</style>
<script>
function runTest() {
    eventSender.dragMode = false;
    eventSender.mouseDown();
    eventSender.mouseUp();

    var target = document.querySelector('body > a');
    var targetRect = target.getBoundingClientRect();

    var posX = parseInt((targetRect.left + targetRect.right) / 2);
    var posY = parseInt((targetRect.top + targetRect.bottom) / 2);
    document.body.offsetLeft;
    eventSender.mouseMoveTo(posX, posY);
}
</script>
</head>
<body onload="runTest()">
  <a href="#">Hover over <b>me</b></a>
</body>
</html>