Using floating boxes
Floating boxes let you manipulate page content to create dynamic effects and multilayered displays. Floating boxes let you divide your page into rectangles that you can format individually, fill with HTML content, and stack. The boxes can be opaque or transparent to reveal objects in the background.

Note: To display properly, floating boxes require Web browsers version 4.0 or later. Although floating boxes may soon be used as commonly as HTML tables, viewers with older browsers may have trouble viewing pages that contain floating boxes.

About floating boxes
Floating boxes are based on the DIV element, which has been available since HTML 3.2 but not commonly used. HTML 4.0 substantially enhances the DIV element's functionality, allowing it to be absolutely positioned, and stacked to accept a background image or background color. The DIV element is also a core element of Dynamic HTML, and a major building block for absolute positioning with cascading style sheets.

Two concepts are key to understanding floating boxes:
* Layering is a key feature of floating boxes. Floating boxes can overlap or even be placed on top of each other. The stacking order is controlled by an attribute called the z-index (z is from the z-axis in a three-dimensional coordinate system). Elements with a higher z-index display on top of elements with a lower z-index. For example, an element with a z-index of 2 appears to float above an element with a z-index of 1. By default, floating boxes are superimposed on the normal flow of HTML and the Adobe GoLive layout grid.

* As an independent division within the page, a floating box accepts any other HTML element-such as an image or simple HTML text with formatting. It also has the same background image and color properties as an HTML page.


上面这段英文对我来说比较难，我觉得我翻译得有点理解不对的地方，大家帮着看看

使用浮动层
你可以使用浮动层将页面内容制作成动态效果和多重显示效果。你可以使用浮动层在页面中划分出拥有独立样式的矩形区域，你可以在该区域中填入HTML内容或是创建更多得的浮动层。你可以通过设定决定浮动层是否可见。

注意：要正确显示浮动层，你必须使用4.0以上版本的Web浏览器。尽管浮动层通常被当作HTML表格来使用，但那些使用老版本浏览器的查看者在查看包含浮动层的页面时仍然可能会出现问题。
关于浮动层
浮动层是派生于DIV（层）元素，该元素最开始出现在HTML 3.2中，但是那时还不常用。HTML 4.0版本增强了DIV元素的功能，允许使用绝对座标来定位层，层的背景可以使用页面的背景图像或背景色。DIV元素也是Dynamic HTML（动态HTML语言）的核心元素，以及CSS（层叠样式表）的主要构件。
要理解浮动层必须掌握以下两个概念：
* 分层是浮动层的一个关键功能。浮动层可以相互重叠甚至可以交换彼此的位置。分层命令被一个名为z-index的属性所控制（这里的z是指三维坐标系统中的z轴）。z-index属性较高的元素会显示在z-index属性较低的元素的上部。例如，z-index属性为2的元素将显示在z-index属性为1元素的上部。默认的浮动层
* 作为页面中的一个独立部分，浮动层可以包含任何其他的HTML元素（例如一个图像或是一段简单的带有格式的HTML文本）。它同HTML页面一样拥有背景图像和背景色属性。