//根据不同的浏览器调用不同的CSS!
if (window.navigator.userAgent.indexOf("MSIE")>=1)
{
	var version = navigator.appVersion;
	var IE7 = 'MSIE 7.0';
	var IE8 = 'MSIE 8.0';
	if(version.match(IE7) === null && version.match(IE8) == 'MSIE 8.0')
	{
		document.write('<link media=\"screen\" href=\"css/msie8.css" type=\"text/css\" rel=\"stylesheet\" />');
	}
	else if(version.match(IE7) == 'MSIE 7.0' && version.match(IE8) === null)
	{
		document.write('<link media=\"screen\" href=\"css/msie7.css" type=\"text/css\" rel=\"stylesheet\" />');
	}
	else
	{
		document.write('<link media=\"screen\" href=\"css/msie6.css" type=\"text/css\" rel=\"stylesheet\" />');
	}
}
else
{
	if (window.navigator.userAgent.indexOf("Firefox")>=1)
	{
		document.write('<link media=\"screen\" href=\"css/firefox.css" type=\"text/css\" rel=\"stylesheet\" />');
	}
	else
	{
		if (navigator.appName=="Opera")
		{
			document.write('<link media=\"screen\" href=\"css/opera.css" type=\"text/css\" rel=\"stylesheet\" />');
		}
		else
		{
			document.write('<link media=\"screen\" href=\"css/msie7.css" type=\"text/css\" rel=\"stylesheet\" />');
		}
	}
}

$(function(){
	$('ul.top_nav li a img').hover(function(){
		var src = $(this).attr('src').split('_');
		var name = src[0] + '_h.gif';
		$(this).attr('src', name);
	},function(){
		var src = $(this).attr('src').split('_');
		var name = src[0] + '_n.gif';
		$(this).attr('src', name);
	});
})