我该怎么做？
我的HTML和CSS文件是这样的：
HTML：
<!doctype html>
<html>
<head>
<link rel="stylesheet" href="../css/style.css" />
<link rel="shortcut icon" href="../favicon.ico" type="image/x-icon" />
<meta charset="utf-8" />
<meta name="author" content="Manpreet Singh (Mannie Cupquake)">
<title>Blac Tree - Home</title>
<script type="text/javascript">
function MM_swapImgRestore() {
var i,x,a=document.MM_sr; for(i=0;a&&i<a.length&&(x=a[i])&&x.oSrc;i++) x.src=x.oSrc;
}
function MM_preloadImages() {
var d=document; if(d.images){ if(!d.MM_p) d.MM_p=new Array();
var i,j=d.MM_p.length,a=MM_preloadImages.arguments; for(i=0; i<a.length; i++)
if (a[i].indexOf("#")!=0){ d.MM_p[j]=new Image; d.MM_p[j++].src=a[i];}}
}
function MM_findObj(n, d) {
var p,i,x; if(!d) d=document; if((p=n.indexOf("?"))>0&&parent.frames.length) {
d=parent.frames[n.substring(p+1)].document; n=n.substring(0,p);}
if(!(x=d[n])&&d.all) x=d.all[n]; for (i=0;!x&&i<d.forms.length;i++) x=d.forms[i][n];
for(i=0;!x&&d.layers&&i<d.layers.length;i++) x=MM_findObj(n,d.layers[i].document);
if(!x && d.getElementById) x=d.getElementById(n); return x;
}
function MM_swapImage() {
var i,j=0,x,a=MM_swapImage.arguments; document.MM_sr=new Array; for(i=0;i<(a.length-2);i+=3)
if ((x=MM_findObj(a[i]))!=null){document.MM_sr[j++]=x; if(!x.oSrc) x.oSrc=x.src; x.src=a[i+2];}
}
</script>
</head>
<body background="../imgz/template/background.png" onLoad="MM_preloadImages('../imgz/buttons/sideHomeOver.png','../imgz/buttons/sideAboutOver.png','../imgz/buttons/sideContactOver.png','../imgz/buttons/sideTwitterOver.png','../imgz/buttons/sideFacebookOver.png','../imgz/buttons/sideYouTubeOver.png')">
<div class="wrapper">
<div class="header">
<div class="headLogo">
</div>
</div>
<div class="_content">
<div class="sidebar">
<br>
<a href="../home/home.htm" onMouseOut="MM_swapImgRestore()" onMouseOver="MM_swapImage('homeButton','','../imgz/buttons/sideHomeOver.png',1)"><img src="../imgz/buttons/sideHome.png" alt="Home" id="homeButton" width="213" height="59" border="0"></a>
<br>
<br>
<a href="../about/about.htm" onMouseOut="MM_swapImgRestore()" onMouseOver="MM_swapImage('aboutButton','','../imgz/buttons/sideAboutOver.png',1)"><img src="../imgz/buttons/sideAbout.png" alt="About" id="aboutButton" width="213" height="58" border="0"></a>
<br>
<br>
<a href="../contact/contact.htm" onMouseOut="MM_swapImgRestore()"onMouseOver="MM_swapImage('contactButton','','../imgz/buttons/sideContactOver.png',1)"><img src="../imgz/buttons/sideContact.png" alt="Contact" id="contactButton" width="213" height="58" border="0"></a>
<br>
<br>
<a href="#" onMouseOut="MM_swapImgRestore()" onMouseOver="MM_swapImage('twitterButton','','../imgz/buttons/sideTwitterOver.png',1)"><img src="../imgz/buttons/sideTwitter.png" alt="Twitter" id="twitterButton" width="60" height="60" border="0"></a>
<a href="#" onMouseOut="MM_swapImgRestore()" onMouseOver="MM_swapImage('facebookButton','','../imgz/buttons/sideFacebookOver.png',1)"><img src="../imgz/buttons/sideFacebook.png" alt="Facebook" id="facebookButton" width="60" height="60" border="0"></a>
<a href="#" onMouseOut="MM_swapImgRestore()" onMouseOver="MM_swapImage('youtubeButton','','../imgz/buttons/sideYouTubeOver.png',1)"><img src="../imgz/buttons/sideYouTube.png" alt="YouTube" id="youtubeButton" width="60" height="60" border="0"></a>
<br>
<br>
<div class="address">
1234 Test Road<br>
West Chester, OH<br>
45069-XX<br>
(513) XXX-XXXX<br>
info@blactree.org
</div>
<br>
<div class="gMap">
</div>
</div>
<div class="contentWrapper">
<div class="ribbon">
<div class="ribbonText">
<div class="font1">
<br>
</div>
About
</div>
</div>
<div class="content">
<p>
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Maecenas a justo ac lectus ornare mattis. Pellentesque volutpat cursus lectus non rhoncus.Maecenas pulvinar, tellus sed laoreet tristique, mauris felis luctus magna, in aliquam ante diam in lectus. Pellentesque habitant morbi tristique senectus et netus et malesuada fames ac turpis egestas. Nam sed purus et ipsum auctor sollicitudin. Sed enim metus, mollis vel dignissim eu, vestibulum id libero. Donec convallis nulla malesuada orci viverra sagittis. Maecenas quis eleifend augue. Proin eu tortor quis lorem suscipit iaculis et feugiat mi. Nullam consequat nulla at nisi ultrices fermentum. Praesent scelerisque lacus et erat mattis condimentum at sed nunc. Cras facilisis nibh quis odio rhoncus lobortis.
<br>
<br>
Vestibulum consequat leo ac enim faucibus vitae cursus leo condimentum. Pellentesque nec dui quis mauris elementum molestie. Donec pellentesque, leo accumsan tincidunt venenatis, urna lectus consequat sapien, sit amet feugiat turpis mi ut sem. Cras id metus et ipsum viverra bibendum eget nec urna. Vestibulum ac metus nec tellus suscipit dignissim vel pellentesque erat. Suspendisse in urna nulla. Pellentesque habitant morbi tristique senectus et netus et malesuada fames ac turpis egestas. Aenean feugiat feugiat aliquam. Duis fermentum massa lectus. Praesent ultricies tincidunt quam a sagittis. Pellentesque interdum dolor non diam ullamcorper suscipit. Proin tempus, est et cursus malesuada, diam lectus suscipit quam, non porttitor augue odio quis massa. Curabitur sit amet gravida lorem. Nullam venenatis, purus vitae egestas semper, arcu urna hendrerit felis, at molestie nisi orci eu urna. Sed venenatis, sapien rhoncus blandit sagittis, nunc felis mollis ipsum, eget aliquam felis turpis et magna. Morbi sapien enim, auctor id venenatis sed, pretium et arcu.
</p>
</div>
</div>
</div>
<div class="footer">
<br>
<br>
Blac Tree © All rights Reserved 2011-2012
</div>
</div>
</body>
</html>
CSS：
@font-face {
font-family: typo_pro_sbi;
src: url('font/typo_pro_sbi.ttf');
}
@font-face {
font-family: typo_pro_eb;
src: url('font/typo_pro_eb.ttf');
}
@font-face {
font-family: bebas_neue;
src: url('font/bebas_neue.otf');
}
.wrapper {
height: auto;
width: 950px;
margin-left: auto;
margin-right: auto;
margin-top: 35px;
}
.wrapper .header {
background: url(../imgz/template/headerBg.png);
background-repeat: no-repeat;
background-position: center center;
height: 143px;
width: 950px;
}
.wrapper .header .headLogo {
background: url(../imgz/template/headerLogo.png);
background-repeat: no-repeat;
background-position: center center;
margin-left: 85px;
height: 136px;
width: 214px;
}
.wrapper ._content {
background-image: url(../imgz/template/contentBg.png);
height: auto;
width: 950px;
}
.wrapper ._content .sidebar {
float: left;
height: auto;
width: 314px;
text-align: center;
}
.wrapper ._content .sidebar .homeButton,.wrapper ._content .sidebar .aboutButton,.wrapper ._content .sidebar .contactButton,.wrapper ._content .sidebar .twitterButton,.wrapper ._content .sidebar .facebookButton,.wrapper ._content .sidebar .youtubeButton {
border: 0px;
}
.wrapper ._content .sidebar .address {
text-align: left;
margin-left: 60px;
font-family: typo_pro_sbi;
color: #9c9c9c;
font-size: 18px;
}
.wrapper ._content .sidebar .gMap {
background-image: url(../imgz/buttons/gMap.png);
background-repeat: no-repeat;
background-position: center center;
text-align: center;
height: 207px;
width: 207px;
margin-left: auto;
margin-right: auto;
}
.wrapper ._content .contentWrapper {
background: url(../imgz/template/contentShadow.png);
background-repeat: repeat-y;
float: left;
height: auto;
width: 563px;
color: #CCCCCC;
}
.wrapper ._content .contentWrapper .ribbon {
background-image: url(../imgz/template/topRibbon.png);
background-repeat: no-repeat;
text-align: center;
height: 113px;
width: 560px;
margin-top: 20px;
}
.wrapper ._content .contentWrapper .ribbon .ribbonText {
font-family: typo_pro_eb;
font-size: 32px;
color: #abd7ff;
}
.wrapper ._content .contentWrapper .ribbon .ribbonText .font1 {
font-size: 22px;
}
.wrapper ._content .contentWrapper .content {
margin-left: auto;
margin-right: auto;
margin-top: 10px;
height: auto;
width: 475px;
overflow: auto;
text-align: left;
font-family: Arial, Helvetica, sans-serif;
font-size: 16px;
font-style: normal;
}
.wrapper .footer {
background-image: url(../imgz/template/footerBg.png);
background-repeat: no-repeat;
height: 80px;
width: 950px;
float: left;
text-align: center;
font-family: bebas_neue;
font-size: 16px;
color: #323232;
}
“_content”类没有显示它应该的背景图像，任何人都可以向我解释原因吗？当我给元素指定一个特定高度时，会出现指定的背景图像，我尝试使用“min-height”，但只有指定的最小高度显示背景图像，我该如何解决？
答案 0 :(得分：0)
可能是因为它的所有孩子都被设置为float: left，这意味着你需要在你的overflow: auto上添加._content这样的东西来让它识别并包裹那些漂浮的元素（而不是只有0高度。
进一步说明：需要清除浮点数，以便它们为其包含的元素赋予高度。清除浮动有多种方法，但最简单的方法是在包含元素上设置overflow属性。