你可以设定
#header {
position: relative;
height: 60px;
}
#login_container {
position: absolute;
right: 0;
top: 60px; /* equal to #header height, if it's not fixed, you should retrieve it dynamically via jQuery */
}
然后动态检索内容的大小并将其应用于登录容器。
<!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=iso-8859-1" />
<title>Documento senza titolo</title>
<style type="text/css">
* {
margin: 0;
padding: 0;
}
#container {
width: 960px;
margin: 0 auto;
position: relative;
}
#login_container {
position: absolute;
right: 0;
width: 100%;
z-index: 10;
}
#content {
position: relative;
z-index: 0;
}
</style>
<!--[if lte IE 6]><style type="text/css"></style><![endif]-->
</head>
<body>
<div id="container">
<div id="header" class="row">
<ul id="topnav">
<li>
<a href="#">a</a>
<span><a href="#">aa</a> <a href="#">ab</a></span>
</li>
<li>
<a href="#">b</a>
<span><a href="#">ba</a> <a href="#">bb</a></span>
</li>
<li style="float: right;"><a href="#">Login</a></li>
</ul>
</div>
<div id="login_container">
<form method="post" id="login_form">
<p>login form</p>
</form>
<form method="post" id="create_account_form">
<p>create account form</p>
</form>
</div>
<div id="content">
content here
</div>
</div>
</body>
</html>
试试看,如果你还有问题就告诉我!