Need to help Jquery for Popup

Dear friend
I use Jquery for popup :

<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.0/jquery.min.js" type="text/javascript"></script>
<script>
$(function() {
var moveLeft = 0;var moveDown = 0;$('a.popper').hover(function(e) { var target = '#' + ($(this).attr('data-popbox')); $(target).show();moveLeft = $(this).outerWidth();moveDown = ($(target).outerHeight() / 2);}, function() {var target = '#' + ($(this).attr('data-popbox'));$(target).hide();});

$('a.popper').mousemove(function(e) {var target = '#' + ($(this).attr('data-popbox'));
leftD = e.pageX + parseInt(moveLeft);
maxRight = leftD + $(target).outerWidth();
windowLeft = $(window).width() - 40;
windowRight = 0;
maxLeft = e.pageX - (parseInt(moveLeft) + $(target).outerWidth() + 20);
if(maxRight > windowLeft && maxLeft > windowRight)
{
leftD = maxLeft;
}
topD = e.pageY - parseInt(moveDown);
maxBottom = parseInt(e.pageY + parseInt(moveDown) + 20);
windowBottom = parseInt(parseInt($(document).scrollTop()) + parseInt($(window).height()));
maxTop = topD;
windowTop = parseInt($(document).scrollTop());
if(maxBottom > windowBottom)
{
topD = windowBottom - $(target).outerHeight() - 20;
} else if(maxTop < windowTop){
topD = windowTop + 20;
}
$(target).css('top', topD).css('left', leftD);
});

});
</script>

CSS
.popbox {
display: none;position: absolute;z-index: 99999;width: 400px;padding: 10px;background: #EEEFEB;color: #000000;border: 1px solid #4D4F53;margin: 0px;-webkit-box-shadow: 0px 0px 5px 0px rgba(164, 164, 164, 1);
box-shadow: 0px 0px 5px 0px rgba(164, 164, 164, 1);
}
.popbox h2
{
background-color: #4D4F53;
color: #E3E5DD;
font-size: 14px;
display: block;
width: 100%;
margin: -10px 0px 8px -10px;
padding: 5px 10px;
}

How fix position in firefox..
Please help me.

Thanks