為什么不在一行呢
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>無標題文檔</title>
<style type="text/css">
/*在此定義相應的類選擇器，并根據要求設置相關CSS屬性*/
.mainBox{
? ? width:960px;
? ? height:300px;
? ? background-color:#CFF;
? ? clear:both;
}
.leftBox{
? ? width:740px;
? ? height:300px;
? ? background-color:#C9F;
? ? float:left;
}
.rightBox{
? ? width:210px;
? ? height:300px;
? ? background-color:#FCF;
? ? float:right;
}
}
</style>
</head>
<body>
<div class='mainBox'></div>
<div class='leftBox'></div>
<div class='rightBox'></div>
<!--在此添加相應的div標簽-->
</body>
</html>
2018-12-30
<div class='mainBox'></div>應該包含<div class='leftBox'></div><div class='rightBox'></div>這倆，你給寫成并列了