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Part III
Adding Advanced Design Features
Generally, you specify values for all four criteria: Left, Top, Right, and Bottom. You can also leave the
Left and Top values empty or use the keyword
auto—which causes the Left and Top values to be set at
the origin point: 0,0. If you leave any of the clipping values blank, the blank attributes are set to
auto.
Z-index
One of an AP element’s most powerful features is its capability to appear above or below other AP
elements. You can change this order, known as the z-index, dynamically. Whenever a new AP ele-
ment is added, Dreamweaver automatically increments the z-index—AP elements with higher
z-index values are positioned above AP elements with lower z-index values. The z-index can be
adjusted manually in either the CSS-P Property inspector or the AP Elements panel. The z-index
must be an integer, either negative or positive.
Although some Web designers use high values for the z-index, such as 3,000, the z-index
is completely relative. The only reason to increase a z-index to an extremely high number
is to ensure that a particular AP element remains on top.
Certain types of objects—including Java applets, plugins, and ActiveX controls—ignore the z-index
setting when included in an AP element and appear as the uppermost AP element. However, cer-
tain plugins controls—most notably Flash—can be made to respect the z-index. If you need H ...