HTML and CSS Reference
3.1. Appearances Can Deceive
Documents never look alike when displayed by a text editor and when
displayed by a browser. Take a look at any source document on the Web.
At the very least, return characters, tabs, and leading spaces, although
important for readability of the source text document, are ignored for
the most part when displayed by an HTML/XHTML browser. There also is
a lot of extra text in a source document, mostly from the display tags
and interactivity markers and their parameters that affect portions of the
document but don't appear in the display.
Accordingly, new authors are confronted with having to develop not only
a presentation style for their web pages, but also a different style for
their source text. The source document's layout should highlight the
programming-like markup aspects of HTML and XHTML, not their display
aspects. And it should be readable not only by you, the author, but by
others as well.
Experienced document writers typically adopt a programming-like style,
albeit very relaxed, for their source text. We do the same throughout this
book, and that style will become apparent as you compare our source
examples with the actual display of the document by a browser.
Our formatting style is simple, but it serves to create readable, easily
• Except for the structural tags such as <html> , <head> , <frameset> ,
and <body> , we place elements that structure the content of a
document on a separate line and indented to show its nesting
level within the document. Structural elements include lists, forms,
tables, and similar tags.
• Elements that control the appearance or style of text get inserted
in the current line of text. These include basic font style tags such
as <b> (bold text) and document linkages such as <a> (hypertext
• Avoid, where possible, breaking a URL onto two lines.