The idea of adding markup instructions to documents is not new. Before computers, authors would make annotations by hand in their written or typed documents. These annotations described what the document should look like when it was typeset. The markup instructions might include a wavy underline to denote italic text, or some information about the font size and faces. With the advent of computers, the markup instructions had to be included within the electronic files which store the data for the document. A computer file stores data, and the rendition of the file is what you see when the computer software reads the file and interprets the markup instructions to see how the data in the file should be rendered on the screen.

Each word processor has its own markup language. You only see the rendition. Word processors are What You See Is What You Get (WYSIWYG) editors. Some word processors have an option which lets you see the markup instructions. The key issue is that each word processor stores the markup instructions in a different proprietary binary format when it saves the data in a file. A word processor file is sometimes called a binary blob. Only the particular software knows what the bytes in the file represent.

HyperText Markup Language (HTML) Uses plain text to add markup instructions to a file. If you can't produce it with a standard keyboard, it can't go into an HTML file. Each byte in the underlying file is an ASCII (American Standard Code for Information Interchange) character -- this is way the Web is application and platform independent. No binary blobs here! The rendition of an HTML file is called a Web page.

OOPS! Elements not nested! Spaces and indentations are only for humans who read and edit the files. Browsers don't care. But Browsers do need the tags to be properly nested.

HTML Syntax Rules The only permissible space in an HTML tag is after the name of the element and before the closing angle bracket.

Some HTML Inline Elements Inline elements’ formatting is applied inline – meaning the page layout flow is not affected.

Some HTML Block Elements Block elements’ formatting is reserves a block in the page layout flow.

Codes for Special Characters These are not standard keyboard characters. CharacterSpecial Code © © ® ® ± ± µ µ The special character codes are used to include them in a Web page.

Others are standard keyboard characters, but browsers think they are part of HTML markup instructions unless their character codes are used. CharacterSpecial Code << > > && Example: See source code for character_codes.html All characters have numerical codes. The Web site includes a complete list. Some characters have non- numeric codes. For example, creates a blank space. This code is used often in the text.

Hiding Directory Listings When a browser request points to a folder instead of a particular file, the server may send you a directory listing. If there is a file named index.html in the directory, then that will load into the browser instead of a directory listing. Some servers use default.html instead or in addition to index.html