Layers were the core of a method of dynamic HTML programming specific to Netscape 4. Each layer was treated as a separate document object in JavaScript. The content could be included in the same file within the non-standard layer element … But in modern browsers, the functionality of layers is provided by using an absolutely-positioned div, or, for loading the content from an external file, an I-Frame.  From Wikipedia, the free encyclopedia

v   Insert Layer:  Use to create a new floating layer.  Each new layer will take a relative position in front or on-top of the previous layer.  The base layer is considered the back ground layer and cannot be moved.

v   Move Forward: Use to move the selected layer forward one level. 

v   Move Backward: Use to move the selected layer back one level.

v   Toggle Absolute Position: Use this to change the layer from a floating layer to one that has and absolute position.