When you put any absolutely positioned elements (not just 'layers') into a
table cell, *some* browsers get confused about how to figure their location.
I put my menu leaf layers in a cell because I wanted the position to be
relative to the cell.
They will not be. They are relative to the location of the nearest
positioned ancestor container (as long as you leave them absolutely
positioned).
This may help you understand positioning a bit -
There are 4 different types of positioning:
Absolute
Relative
Fixed
Static
Here is a brief explanation of each kind of positioning (with regard to
placement of elements on the page only)....
Position:absolute (or A/P elements)
-----------------------
This does several things -
1. It 'removes' the element from the flow of the code on the page so that
it can no longer influence the size or position of any other page element
(except for those contained within it, of course).
2. The absolutely positioned element takes its position from the position of
its closest PARENT *positioned* element - in the absence of any explicitly
positioned parent, this will default to the <body> tag, which is always
positioned
at 0,0 in the browser viewport.
This means that it doesn't matter where in the HTML code the layer's code
appears (between <body> and </body>), its location on the screen will not
change (this assumes that you have not positioned the A/P element within
a table or another A/P element, of course). Furthermore, the space in
which
this element would have appeared were it not positioned is not preserved
on the screen. In other words, absolutely positioned elements don't take
up any space on the page. In fact, they FLOAT over the page.
Position:relative (or R/P elements)
----------------------
In contrast to absolute positioning, a relatively positioned page element is
*not* removed from the flow of the code on the page, so it will use the
spot
where it would have appeared based on its position in the code as its
zero point reference. If you then supply top, right, bottom, or left
positions
to the style for this element, those values will be used as offsets from
its
zero point.
This means that it DOES matter where in the code the relatively positioned
element appears (, as it will be positioned in that location (factoring in
the offsets) on the screen (this is true for any placement in the code).
Furthermore, the space where this element would have appeared is
preserved in the display, and can therefore affect the placement of
succeeding elements. This means that the taller a relatively
positioned element is, the more space it forces on the page.
Position:static
-------------------
As with relative position, static positions also "go with the flow". An
element with a static position cannot have values for offsets (top, right,
left, bottom) or if it has them, they will be ignored. Unless explicitly
positioned, all div elements default to static positioning.
Position:fixed
------------------
A page element with this style will not scroll as the page content scrolls.
Support for this in elements other than page backgrounds is quirky
There are several other things you need to know:
1. ANY page element can be positioned - paragraphs, tables, images, lists,
etc.
2. The <div> tag is a BLOCK level tag. This means that if it is not
positioned or explicitly styled otherwise, a) it will always begin on a new
line on the screen, and b) it will always force content to a new line below
it, and c) it will always take up the entire width of its container (i.e.,
width:100%).
3. The placement of A/P elements *can* affect the BEHAVIOR of other
elements
on the page. For example, a 'layer' placed over a hyperlink will mask that
hyperlink.
You can see a good example of the essential difference between absolute and
relative positioning here -
http://www.great-web-sights.com/g_layersdemo.asp
You can see a good demonstration of why using layers for a page layout tool
is dangerous here -
http://www.great-web-sights.com/g_layer-overlap.asp
