Many of us tend to use the terms LAYER and DIV interchangeably, butÂ there is a difference.
LAYER – A LAYER (in Dreamweaver terminology) is an absolutely positioned DIV which tends to “float” outside/above the page flow. Dreamweaver allows you to insert (or draw) a LAYER in a document, and you can “grab” a LAYER and drag it all over the page. Playing with LAYERs can be fun, but building pages with LAYERs can result in unintended consequences. You can see an example here.
DIV – When the position of a DIV is omitted (no top, left, right, or bottom properties), the DIV is static. A static DIV is a page DIVision that exists in the logical flow of a page. A static DIV is like a box, and inside the boxes you can place headings, paragraphs, images, tables. etc.
1) All LAYERs are DIVs (absolutely positioned), but not all DIVs are LAYERs.
2) We need to be careful when using LAYERs because they “float” above a page and can cover other items on the page.
3) A normal or static DIV is not absolutely positioned; it is merely a division that exists in the normal flow of a page.