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A CSS page layout uses the Cascading Style Sheets format, rather than traditional HTML tables or frames, to organize the content on a web page. The basic building block of the CSS layout is the div tag—an HTML tag that in most cases acts as a container for text, images, and other page elements. When you create a CSS layout, you place div tags on the page, add content to them, and position them in various places. Unlike table cells, which are restricted to existing somewhere within the rows and columns of a table, div tags can appear anywhere on a web page. You can position div tags absolutely (by specifying x and y coordinates), or relatively (by specifying its location with respect to its current location). You can also position div tags by specifying floats, paddings, and margins—the preferred method by today’s web standards.
Before proceeding with this section, you should be familiar with basic CSS concepts.
The basic building block of the CSS layout is the div tag—an HTML tag that in most cases acts as a container for text, images, and other page elements. The following example shows an HTML page that contains three separate div tags: one large “container” tag, and two other tags—a sidebar tag, and a main content tag—within the container tag.
<!--container div tag-->
<div id="container">
<!--sidebar div tag-->
<div id="sidebar">
<h3>Sidebar Content</h3>
<p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit.</p>
<p>Maecenas urna purus, fermentum id, molestie in, commodo porttitor, felis.</p>
</div>
<!--mainContent div tag-->
<div id="mainContent">
<h1> Main Content </h1>
<p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Praesent aliquam, justo convallis luctus rutrum.</p>
<p>Phasellus tristique purus a augue condimentum adipiscing. Aenean sagittis. Etiam leo pede, rhoncus venenatis, tristique in, vulputate at, odio.</p>
<h2>H2 level heading </h2>
<p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Praesent aliquam, justo convallis luctus rutrum, erat nulla fermentum diam, at nonummy quam ante ac quam.</p>
</div>
</div>
In the above example, there is no “styling” attached to any of the div tags. Without CSS rules defined, each div tag and its contents fall into a default location on the page. However, if each div tag has a unique id (as in the above example), you can use the ids to create CSS rules that, when applied, change the style and positioning of the div tags.
The following CSS rule, which can reside in the head of the document or in an external CSS file, creates styling rules for the first, or “container” div tag on the page:
#container {
width: 780px;
background: #FFFFFF;
margin: 0 auto;
border: 1px solid #000000;
text-align: left;
}
The #container rule styles the container div tag to have a width of 780 pixels, a white background, no margin (from the left side of the page), a solid, black, 1‑pixel border, and text that is aligned left. The results of applying the rule to the container div tag are as follows:
A. Text aligned left B. White background C. 1-pixel solid black border
#sidebar {
float: left;
width: 200px;
background: #EBEBEB;
padding: 15px 10px 15px 20px;
}
The #sidebar rule styles the sidebar div tag to have a width of 200 pixels, a gray background, a top and bottom padding of 15 pixels, a right padding of 10 pixels, and a left padding of 20 pixels. (The default order for padding is top-right-bottom-left.) Additionally, the rule positions the sidebar div tag with float: left—a property that pushes the sidebar div tag to the left side of the container div tag. The results of applying the rule to the sidebar div tag are as follows:
A. Width 200 pixels B. Top and bottom padding, 15 pixels
#mainContent {
margin: 0 0 0 250px;
padding: 0 20px 20px 20px;
}
The #mainContent rule styles the main content div with a left margin of 250 pixels, which means that it places 250 pixels of space between the left side of the container div, and the left side of the main content div. Additionally, the rule provides for 20 pixels of spacing on the right, bottom, and left sides of the main content div. The results of applying the rule to the mainContent div are as follows:
The complete code looks as follows:
A. 20 pixels left padding B. 20 pixels right padding C. 20 pixels bottom padding
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>Untitled Document</title>
<style type="text/css">
#container {
width: 780px;
background: #FFFFFF;
margin: 0 auto;
border: 1px solid #000000;
text-align: left;
}
#sidebar {
float: left;
width: 200px;
background: #EBEBEB;
padding: 15px 10px 15px 20px;
}
#mainContent {
margin: 0 0 0 250px;
padding: 0 20px 20px 20px;
}
</style>
</head>
<body>
<!--container div tag-->
<div id="container">
<!--sidebar div tag-->
<div id="sidebar">
<h3>Sidebar Content</h3>
<p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit.</p>
<p>Maecenas urna purus, fermentum id, molestie in, commodo porttitor, felis.</p>
</div>
<!--mainContent div tag-->
<div id="mainContent">
<h1> Main Content </h1>
<p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Praesent aliquam, justo convallis luctus rutrum.</p>
<p>Phasellus tristique purus a augue condimentum adipiscing. Aenean sagittis. Etiam leo pede, rhoncus venenatis, tristique in, vulputate at, odio.</p>
<h2>H2 level heading </h2>
<p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Praesent aliquam, justo convallis luctus rutrum, erat nulla fermentum diam, at nonummy quam ante ac quam.</p>
</div>
</div>
</body>
Opomba:
The above example code is a simplified version of the code that creates the two-column fixed left sidebar layout when you create a new document using the predesigned layouts that come with Dreamweaver.
When creating a new page in Dreamweaver, you can create one that already contains a CSS layout. Dreamweaver comes with 16 different CSS layouts that you can choose from. Additionally, you can create your own CSS layouts and add them to the configuration folder so that they appear as layout choices in the New Document dialog box.
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Opomba:
You must select an HTML page type for the layout. For example, you can select HTML, ColdFusion®, PHP, and so on. You cannot create an ActionScript™, CSS, Library Item, JavaScript, XML, XSLT, or ColdFusion Component page with a CSS layout. Page types in the Other category of the New Document dialog box are also restricted from including CSS page layouts.
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For Layout, select the CSS layout you want to use. You can choose from 16 different layouts. The Preview window shows the layout and gives a brief description of the selected layout.
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- If you selected Create New File from the Layout CSS pop‑up menu, click Create, and then specify a name for the new external file in the Save Style Sheet File As dialog box.
- If you selected Link to Existing File from the Layout CSS in pop‑up menu, add the external file to the Attach CSS file text box by clicking the Add Style Sheet icon, completing the Attach External Style Sheet dialog box, and clicking OK. When you’re finished, click Create in the New Document dialog box.
Opomba:
When you select the Link to Existing File option, the file you specify must already have the rules for the CSS file contained within it.
When you put the layout CSS in a new file or link to an existing file, Dreamweaver automatically links the file to the HTML page you’re creating.
Opomba:
Internet Explorer conditional comments (CCs), which help work around IE rendering issues, remain embedded in the head of the new CSS layout document, even if you select New External File or Existing External File as the location for your layout CSS.
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(Optional) You can also attach CSS style sheets to your new page (unrelated to the CSS layout) when you create the page. To do this, click the Attach Style Sheet icon above the Attach CSS file pane and select a CSS style sheet.
For a detailed walk-through of this process, see David Powers’s article, Automatically attaching a style sheet to new documents.
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Create an HTML page that contains the CSS layout you’d like to add to the list of choices in the New Document dialog box. The CSS for the layout must reside in the head of the HTML page.
Opomba:
To make your custom CSS layout consistent with the other layouts that come with Dreamweaver, you should save your HTML file with the .htm extension.
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(Optional) Add a preview image of your layout (for example a .gif or .png file) to the Adobe Dreamweaver CS5\Configuration\BuiltIn\Layouts folder. The default images that come with Dreamweaver are 227 pixels wide x 193 pixels high PNG files.
Opomba:
Give your preview image the same file name as your HTML file so that you can easily keep track of it. For example, if your HTML file is called myCustomLayout.htm, call your preview image myCustomLayout.png.
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(Optional) Create a notes file for your custom layout by opening the Adobe Dreamweaver CS5\Configuration\BuiltIn\Layouts\_notes folder, copying and pasting any of the existing notes files in the same folder, and renaming the copy for your custom layout. For example, you could copy the oneColElsCtr.htm.mno file, and rename it myCustomLayout.htm.mno.