<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<script>

function boom()
{
    document.setUserData('key', {}, null);

    // Depending on the pref bidi.direction, one of these will hit the page scrollbar.
    window.cpRight = document.caretPositionFromPoint(window.innerWidth - 1, 0);
    window.cpLeft = document.caretPositionFromPoint(0, 0);
}

</script>
</head>

<body onload="boom();">
<div style="height: 50000px;"></div>
</body>
</html>
