IE/LIs with onmouseover/image reloading problem

I have a bunch of LIs with a background image on them.  When I mouse over
the LI it's class changes (using a small bit of JS).  The background image
gets reloaded each time, making it a very flickery effect....


javascript
---------------
function $(e){return document.getElementById(e);}

function init()
{
	if ($('apps'))
	{
		var e = $('apps').getElementsByTagName('li');

		var over=function(){this.className='hover';};
		var out=function(){this.className='';};

		for(i=0,l=e.length; i<l; i++)
		{
			e[i].onmouseover=over;
			e[i].onmouseout=out;
		}
	}
}

if (window.attachEvent)
	window.attachEvent('onload',init);
else
	window.addEventListener('load',init,false);


CSS
-------------------------
#apps{margin:-10px -10px 0 -10px;}
#apps li{padding:6px 6px 0 50px;border-bottom:1px solid
#d2d2d2;cursor:pointer;border-top:1px solid
#fff;background-repeat:no-repeat;background-position: 8px 12px;}
#apps li.hover{background-color:#dedede;}
#apps li a{color:#666;}
#apps li a:hover, #apps li a:active{background:transparent;color:#666;}
#apps li#a_jt{background-image:url(/images/apps_jobtrack.gif);}
#apps li#a_rec{background-image:url(/images/apps_reccrm.gif);}
#apps li#a_crm{background-image:url(/images/apps_crm.gif);}
#apps li#a_cp{background-image:url(/images/apps_creatorpro.gif);}
#apps li#a_s{background-image:url(/images/apps_sms.gif);}
#apps li#a_q{background-image:url(/images/apps_questions.gif);}


HTML
------------------
<ul id="apps">
	<li id="a_jt">
		<h4><a href="#" title="Job Board Software">Job Board Software</a></h4>
		<p>Award-winning job board software</p>
	</li>
	<li id="a_rec">
		<h4><a href="#" title="Recruitment Software">Recruitment CRM</a></h4>
		<p>Delivering an integrated system via the Internet</p>
	</li>



Any ideas?  cheers guys.  Might be related to the other email I sent out a
couple of minutes ago?



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