Liquid layout
A page layout is the way a page’s content is divided across regions.
Goals
A liquid layout uses the full width of the browser window. It changes its width when the user resizes the browser window. Like this:

Figure 1. Liquid layout
Usually, the left and right regions remain the same width. The center region expands and contracts.
Implementation
Here is a sample layout:

Figure 2. Liquid layout with no whitespace
Here is the code that makes it:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Liquid layout</title>
<style type="text/css">
* {
margin: 0;
padding: 0;
}
body {
font-family: Verdana, Helvetica, sans-serif;
font-size: 14px;
}
#top_region {
background-color: #E0E0E0;
}
#left_region {
float: left;
width: 120px;
background-color: #defee2;
}
#center_region {
margin-left: 120px;
margin-right: 120px;
background-color: #fdffca;
}
#right_region {
float: right;
width: 120px;
background-color: #ddddff;
}
#bottom_region {
background-color: #E0E0E0;
}
</style>
</head>
<body>
<div id="top_region">
<p>Top region</p>
</div>
<div id="left_region">
<p>Left region</p>
</div>
<div id="right_region">
<p>Right region</p>
</div>
<div id="center_region">
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit,
sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi
ut aliquip ex ea commodo consequat. </p>
</div>
<div id="bottom_region">
<p>Bottom region</p>
</div>
</body>
</html>
Figure 3. Code for liquid layout with no whitespace
Sometimes you want whitespace between the regions, like this:

Figure 4. Liquid layout with whitespace
If you want spacing, add padding and margins.
#top_region {
background-color: #E0E0E0;
padding: 5px;
margin: 5px;
}
#left_region {
float: left;
width: 120px;
background-color: #defee2;
padding: 5px;
margin: 0 5px 5px 5px;
}
#center_region {
margin: 0 140px 5px 140px;
background-color: #fdffca;
padding: 5px;
}
#right_region {
float: right;
width: 120px;
background-color: #ddddff;
padding: 5px;
margin: 0 5px 5px 5px;
}
#bottom_region {
background-color: #E0E0E0;
padding: 5px;
margin: 0 5px 0 5px;
}
Figure 5. Adding whitespace
Comments
The width of the center region is not predictable. Images that look good at one browser size may not look good in other browser sizes.