//utilise la technique : http://www.webresourcesdepot.com/smart-floating-banners/
/*
<div id="sky_right" style="float:left;">
</div>
<div style="float:right;width:120px;" class="floating_sky_top">
	<div class="floating_sky" style="background-color:#F4F4F4;height:600px;">
		<img src="...">
	</div>
</div>';
<div class="cleaner"></div>
*/
$(window).scroll(function() {

	if ($(".floating_sky_top").offset()==null)
		return;

	if  ($(window).scrollTop() > $(".floating_sky_top").offset().top) //il faut descendre le banner
	{
		//if ($(window).scrollTop()+$(".floating_sky").height() < $("#sky_right").offset().top+$("#sky_right").height())
		//$(".floating_sky").css("position", "relative");

		if ($("#sky_right").offset().top + $("#sky_right").height() > $(".floating_sky").offset().top+$(".floating_sky").height())
			$(".floating_sky").css("margin-top",$(window).scrollTop()-$(".floating_sky_top").offset().top);
		/*
		else
			$(".floating_sky").css("margin-top",$("#sky_right").height() - $(".floating_sky").height() );*/
	}
	else //retour pos initiale
	{
			$(".floating_sky").css("margin-top", "0");
	}

});