Layer Element

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 (or any other element with the positioning set to "absolute" via CSS) or loaded from a separate file with or

. It could also be generated via JavaScript with the layer = new Layer constructor. The content would then be inserted into the layer with layer.document.write.

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 IFrame.

Irrelevant to the actual use of layers, when Netscape 4 and Internet Explorer had significantly different JavaScript implementations, a JavaScript program would very often need to run different blocks of code, depending on the browser. To decide which bunches of code to run, a JavaScript program would test for support for layers, regardless of whether the program involved layers at all. Namely,

if( document.layers ) { ...code that would be executed only by Netscape browsers... } else { ...code that would be executed only by Internet Explorer... }

Famous quotes containing the words layer and/or element:

    “The writer in me can look as far as an African-American woman and stop. Often that writer looks through the African-American woman. Race is a layer of being, but not a culmination.”
    —Thylias Moss, African American poet. As quoted in the Wall Street Journal (May 12, 1994)

    “All forms of beauty, like all possible phenomena, contain an element of the eternal and an element of the transitory—of the absolute and of the particular. Absolute and eternal beauty does not exist, or rather it is only an abstraction creamed from the general surface of different beauties. The particular element in each manifestation comes from the emotions: and just as we have our own particular emotions, so we have our own beauty.”
    —Charles Baudelaire (1821–1867)