Types of Styles Sheets

There are several ways of inserting styles; these methods include external styles, internal styles, and inline styles. There is an order of priority to these different styles. Basically, the more specific and the closer the rule, the more priority it has. The priority list is as follows:

1. Inline Styles
2. Internal Style Sheet
3. @import for External Style Sheet
4. External Style Sheet

External Style Sheet

An external style sheet is ideal when the style is applied to many pages. With an external style sheet, you can change the look of an entire Web site by changing one file. Each page must link to the style sheet using the link tag. The link tag goes inside the head section:

The browser will read the style definitions from the file mystyle.css, and format the document according to it.

How to use the link tag to link to an external style sheet:

An external style sheet can be written in any text editor. The file should not contain any html tags. Your style sheet should be saved with a .css extension. An example of a style sheet file is shown below:

hr {color: sienna}
p {margin-left: 20px}
body {background-image: url("images/back40.gif")}

Do NOT leave spaces between the property value and the units! If you use “margin-left: 20 px” instead of “margin-left: 20px” it will only work properly in IE6 but it will not work in Mozilla/Firefox or Netscape.

Internal Style Sheet

An internal style sheet should be used when a single document has a unique style. You define internal styles in the head section by using the style tag, like this:

The browser will now read the style definitions, and format the document according to it.

Note: A browser normally ignores unknown tags. This means that an old browser that does not support styles, will ignore the p tag, but the content of the tag will be displayed on the page. It is possible to prevent an old browser from displaying the content by hiding it in the HTML comment element:

Inline Styles

An inline style loses many of the advantages of style sheets by mixing content with presentation. Use this method sparingly, such as when a style is to be applied to a single occurrence of an element.

To use inline styles you use the style attribute in the relevant tag. The style attribute can contain any CSS property. The example shows how to change the color and the left margin of a paragraph:

This is a paragraph