Book HomeCascading Style Sheets: The Definitive GuideSearch this book Friday 28th of August 2015 02:10:07 AM

10.5. Adapting to the Environment

CSS2 offers the ability to both alter the browser's environment and integrate its look more closely to that of the user's operating system.

10.5.1. Cursors

To achieve the former, we have the cursor property, which lets you declare what shape the browser's cursor will take as it passes over a given element. Want to make a humorous point about download times? Change the cursor to the wait cursor (an hourglass or watch) when the cursor passes over hyperlinks. You can even hook this property up to "cursor files" (which are not defined by the specification), so you could theoretically class your anchors based on where they go and load different icons for each type of link. For example, off-site links could cause the cursor to change into a globe, while links intended to provide help could trigger a question-mark cursor.

10.5.2. Colors

In order to let web pages more closely match the user's desktop environment, there are a whole list of new color keywords like button-highlight, three-d-shadow, and gray-text. These are all intended to use the colors of the user's operating system. In all, there are 27 of these new color keywords. I won't list them all out here, but they're listed in Table 10-1, found at the end of this chapter.

10.5.3. Outlines

While you're moving your cursor around, you might want to show where the focus is set. For example, it might be nice to define a button so that it gets a red box around it when the cursor moves over it. Well, there a number of outline properties, including outline, outline-color, outline-style, and outline-width. To use the example of a red box, you might declare:

IMG.button:hover {outline: solid red 1px;}

This should have the effect described. The outline styles could also be used to set a visible outline for regions in a client-side image map.



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similar to the somewhat famous JavaScript "rollover"trick, where images change when the pointer hovers over them. Thanksto :hover, you can specify a hover style veryeasily:

A:link {background: white; color: blue;}A:hover {background: blue; color: white;}

These styles will cause anchors to "reverse" in colorwhen the mouse pointer hovers over them, as illustrated in Figure 10-9.

the specification show that it is the outer edges that are offset.

The implication of offsetting the outer edges of a positioned element is that everything about an element -- margins, borders, padding, and content -- is moved in the process of positioning the element. In other words, it is possible to set margins, borders, and padding for a positioned element. These will be preserved and kept with the positioned element, and will be contained within the area defined by the side-offset properties.