Chapter 14. Layer Behaviors
Layers provide a third dimension to your web documents—they can be stacked like glass plates so their contents overlap. Layers also offer absolute positioning of elements in a document. You can create visual effects by modifying a layer’s visibility, contents, and position over time.
Layer Size and Position
Layers require 4.0+ versions of the major
browsers. For maximum compatibility with
Netscape Navigator and Internet Explorer, create layers using the
<div>
tag. For example, a layer implemented
with a <div>
tag using absolute positioning
might look like this:
<div id="Layer1" style="position:absolute; visibility:visible; left:67px; top:39px; width:161px; height:172px; z-index:1; overflow:scroll"> </div>
Avoid
<span>
tags, which work in IE only, and avoid
<layer>
and
<ilayer>
tags, which work in NN4.x only. For
more details, see Section 4.2 in
Chapter 4.
Layers are controlled using the attributes discussed in Table 4-5. These attributes can be set in the Property
inspector, as shown in Figure 4-7. A script can
reference a layer’s id
(in this case,
Layer1
) to modify its properties. By default, when
you add a layer to your document, Dreamweaver adds the
MM_reloadPage
behavior to ensure that layers are
properly updated when resizing the Netscape browser window. If your
site does not support Netscape browsers, you can shut this option off
under Edit → Preferences → Layers → Netscape 4 Compatibility. You can add or remove this JavaScript manually in a document ...
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