What are Cascading Style Sheets? continued

• To properly see the effects of the Style Sheets, your visitors will need to use a web browser that is version 4.0 or newer. Fortunately, using CSS does not cause web pages to break when viewed on older browsers; however, the styles won’t appear as defined. Since most people these days are using Internet Explorer 6, Netscape 7, or Firefox 1 or newer, most browsers can properly display CSS.

• CSS-aware browsers apply their own stylesheet for every HTML element as the first set of rules in the cascade, and this set of rules form the default display for every element. For example, most browsers treat the <p> tag as a block element, as though there were the explicit declaration p { display: block;} By using CSS, you modify the default settings by overriding these implicit styles with an explicit declaration (for more on the block display, see slide 17).

• By using CSS, you can also control text formatting and location on the page. Using CSS can eliminate the need for tables as a layout tool. With CSS, logos can be created using just text, instead of having to rely on graphics. These changes make pages more accessible to a wider audience.

• CSS Specifications:

• • CSS 1: http://www.w3.org/TR/REC-CSS1-961217.html
  • CSS 2: http://www.w3.org/TR/CSS2/
  • CSS 2.1: http://www.w3.org/TR/CSS21/

• Differences between CSS 1, CSS 2, and CSS 2.1:

• • Between CSS 1 and CSS 2: http://www.w3.org/TR/CSS2/changes.html
  • Between CSS 2 and CSS 2.1: http://www.w3.org/TR/CSS21/changes.html