<html>
<head>
<title></title>
<style type="text/css">
* {
    color:red;
    font-size:48px;
}
.description {
    color:black;
    font-size:16px;
}
p:first-line {
    color:green;
}
p:first-letter {
    background-color:pink;
}
p:hover {
  /* empty */
}
</style>

<script type="text/javascript">
function test()
{
    if (!window.eventSender)
        return;
    document.body.offsetTop; // Force layout. The mouse is not tracked before first layout.
    eventSender.mouseMoveTo(24, 24); // Hover.
    document.body.offsetTop; // Update layout for hovered state.
}
</script>

</head>
<body onload="test()">
<p>
ABCDEFG<br/>
<span class="description">
Hover over "A". It must stay green.
</span>
</p>
</body>
</html>