                        課程
                    
                        /前端開發
                        
                            /HTML/CSS
                        
                        /企業網站綜合布局實戰

頁面出現了個小問題，求教

在chrome里面正常顯示，在FF和IE里，導航左邊的圖片浮動到上面去了，請教怎么回事

<!DOCTYPE?html>
<html>
<head>
????<meta?charset="UTF-8">
????<title>慕課網</title>
????<link?href="css/style.css"?rel="stylesheet"?type="text/css"/>
????<script?type="text/javascript"?src="js/setHomeSetFav.js"></script>
????<script?type="text/javascript"?src="js/script.js"></script>
????<script?type="text/javascript"?src="js/myfocus-2.0.1.min.js"></script>
????<script?type="text/javascript"?src="js/mf-pattern/mF_liquid.js"></script>
????<link?rel="stylesheet"?type="text/css"?href="js/mf-pattern/mF_liquid.css"?/>
????<script?type="text/javascript">
?????myFocus.set({
?????id:"picBox"
?????})
????</script>
</head>
<body>
<div>
???<div>
???????<ul>
???????????<li><a?href="#"?id="contactUs">聯系我們</a></li>
???????????<li><a?href="#"?id="setFav">加入收藏</a></li>
???????????<li><a?href="#"?id="setHomepage">設為首頁</a></li>
???????</ul>
???</div>
</div><!--top結束-->
<div>
<div>
<div>
???<a?href="index.html">
<img?src="images/logo.jpg"?alt="慕課網"?/>
</a>
</div>
<div>
<img?src="images/tel.jpg"?alt="tel"?/>
電話熱線:<span>123-456-7890</span>
</div>
</div><!--?logo結束?-->
<div>
<div></div>
<div>
<div>
<ul>
<li><a?href="#">首頁</a></li>
<li><a?href="list.html"?target="_blank">關于慕課</a></li>
<li><a?href="list.html"?target="_blank">新聞動態</a></li>
<li><a?href="list.html"?target="_blank">課程中心</a></li>
<li><a?href="list.html"?target="_blank">在線課程</a></li>
<li><a?href="list.html"?target="_blank">人才招聘</a></li>
</ul>
</div>
<div>
<form?action=""?method="post">
<input?type="text"?name="search">
</form>
</div>
</div><!--?nav_mid結束?-->
<div></div>
</div><!--?nav結束?-->

*{
	padding:?0;
	margin:?0;
	font-size:?12px;
}

body{
	background-color:?#f3f3f3;
}

.top{
	height:?27px;
	width:?100%;
	background:?url("../images/top_bg.jpg")?repeat-x;
}

.top_content{
	width:?1000px;
	height:?100%;
	margin:?0?auto;
}

.top_content?li{
	float:?right;
	list-style-image:?url("../images/li_bg.gif");
	width:?70px;
	line-height:?27px;
}

.top_content?a:link,.top_content?a:visited{
	color:?#8e8e8e;
	text-decoration:?none;
}

.top_content?a:hover,.top_content?a:active{
	color:?#900;
	text-decoration:?none;
}

.wrap?{
	width:?1000px;
	margin:?0?auto;
}

.logo?{
	height:?83px;
	background-color:?#fff;
	clear:?both;
}

.wrap?.logo?.logo_left?{
?????width:?200px;
?????float:?left;
?????padding-top:?
}

.wrap?.logo?.logo_right?{
	width:?250px;
	float:?right;
	margin-top:?25px;
}

.wrap?.logo?.logo_right?img{
	vertical-align:?middle;
}

.wrap?.logo?.logo_right?span{
	color:?red;
	font-family:?'微軟雅黑';
	font-size:?14px;

}

.wrap?.nav{
????
	height:?40px;
}


.wrap?.nav?.nav_left{
	width:?10px;
	background:?url("../images/nav_left.jpg")?no-repeat;
}

.wrap?.nav?.nav_right{
	width:?10px;
	background:?url("../images/nav_right.jpg")?no-repeat;
}

.wrap?.nav?.nav_mid{
	width:?980px;
	background:?url("../images/nav_bg.jpg")?repeat-x;
}

.ad{
	clear:?both;
}

.wrap?.nav?.nav_left,.wrap?.nav?.nav_right,.wrap?.nav?.nav_mid?{
	height:?40px;
	float:?left;
}

.wrap?.nav?.nav_mid?.nav_mid_left{
	width:?680px;
}

.wrap?.nav?.nav_mid?.nav_mid_right{
	width:?300px;
}

.wrap?.nav?.nav_mid?.nav_mid_left,.wrap?.nav?.nav_mid?.nav_mid_right{
???float:?left;

}

.wrap?.nav?.nav_mid?.nav_mid_left?li{
	float:?left;
	width:?100px;
	list-style-type:?none;
	line-height:?40px;
	text-align:?center;
}

.wrap?.nav?.nav_mid?.nav_mid_left?li?a:link,.wrap?.nav?.nav_mid?.nav_mid_left?li?a:visited{
	color:?#fff;
	text-decoration:?none;
	font-family:?"Microsoft?Yahei";
	font-size:?16px;
}

.wrap?.nav?.nav_mid?.nav_mid_left?li?a:hover,.wrap?.nav?.nav_mid?.nav_mid_left?li?a:active{
	color:?#ff0;
	text-decoration:?none;
	font-family:?"Microsoft?Yahei";
	font-size:?16px;
}

.wrap?.nav?.nav_mid?.nav_mid_right?.search_text{
	width:?230px;
	height:?20px;
	margin-top:?8px;
	background:?url("../images/search.jpg")?no-repeat?right?center;
	background-color:?#fff;
	padding-right:?26px;
}