Accessibility and Dreamweaver MX 2004 - Cascading Stylesheets
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In Macromedia Dreamweaver MX 2004, Cascading Stylesheets are the default method for formatting text. This has significant implications for accessibility. Although use of CSS is not required under Section 508, it is required under policies in the UK, Canada, Germany, and several U.S. states. This section reviews some of the key benefits as well as the new features introduced in this latest release.
One of the central tenets of accessibility is the separation of presentation from structure. In very simple terms, this can mean using HTML to control the hierarchical organization of a document and CSS to control the formatting. As you saw in Chapter 2, CSS is a tremendously powerful technology because it allows the end user the capability to easily render the text in the manner that best meets his or her needs.
User-defined stylesheets are attached to a page by the user via the browser. They allow users to format text. Users with limited vision can change the text size and users who are colorblind can change the text and background colors.
The last stop in the cascade is HTML. This is important to note because HTML overrides all CSS styles, including user-defined styles. Using the element to mark up text removes the user’s control over the formatting of text. Mixing HTML presentation together with CSS limits the user’s ability to control the formatting on the page. Even in a simple example such as the use of background images can serve as a tremendous obstacle. For colorblind users, black text on a white background can be significantly easier to read. However, if the background image is coded using HTML as opposed to CSS, they will not be able to use user-defined stylesheets to replace the background image, even if the text is formatted using CSS. The HTML will always override the CSS and thus the background image can not easily be removed by the user.
Dreamweaver MX 2004 uses CSS to format text by default. When choosing a font from the Properties inspector, an internal style is automatically created and added to the page. The size menu has also changed in this release. Designers can now specify sizes using a variety of units available via CSS. Finally, custom styles, also called class selectors, can be applied directly from the Style menu on the Properties inspector, as shown in Figure 3-16. This menu provides designers with a preview of each style to help facilitate consistent use of each style.
Figure 3-16. Previewing styles on the Style menu
There is one significant concern worth noting when it comes to the use of CSS—fixed units such as points and millimeters prevent the user from changing the text size on the screen. Although designers often want to exert precise control over text for layout and design reasons, it is important to remember that many users use the text size control in their browser to make small text easy to read. Using relative units such as ems and percentage provides users with a level of control over the text size.
 This chapter is from ASP Web Development with Macromedia Dreamweaver MX 2004, by Rachel Andrew et al., (Apress, 2004, ISBN: 1590593499). Check it out at your favorite bookstore today.
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