411 REFERENCE · Wikibooks
HyperText Markup Language/Layers
Reference material by Wikibooks contributors. This retains its source identity and is not 411 news reporting.
Layers are not a part of HTML 4.01 or XHTML. They were a proprietary element created by Netscape. You can achieve the same effect using CSS's z-index property.
Confusingly, Dreamweaver has a layers feature which is functionally similar but is based on div elements styled with CSS and optionally animated with Javascript.