lectureMini-lecture on HTML, SGML, etc.
No doubt you have visited many Web sites with your browser and seen that the full address of the Web page ends in "html." But you may not know what "html" stands for or why it is part of virtually every Web page address (even if it is not explicitly stated, but assumed as the default). Supplemental links 
(not a required part of the course)
HTML stands for Hypertext Markup Language. An HTML document is a text document that has been "marked up," which means it now includes "meta-information," or information about the information contained in the document.  This meta-information relates to the document structure and appearance (how it should be displayed). The browser uses most of this markup to display the document on a computer screen. CSE 3310 
HTML Validator Lite
(a program that will check
 your HTML for
 correctness)

The marking up is done by including "tags" in the document. For example, there is a tag that tells the browser what the title of the document is. The opening tag <TITLE> goes before the text that is the title, and the closing tag </TITLE> goes after the text. There are tags for bold text, for blinking text, for block quotes, for tables, for including images, and so on.  When a browser encounters a tag in an HTML document, it follows the directions for display that the tag calls for, unless it doesn’t understand the tag, in which case it ignores the tag.

For example, this HTML calls for bold text:

<BOLD> Some bold text.</BOLD>

Here is how a browser would display the line:

Some bold text.
Before computers, a text was "marked up" in order to tell a printer how the document should be printed--what words should be bold, what passages should be omitted, etc.  Later, proprietary software programs were written to prepare electronic documents for typesetting.

HTML and other related systems of marking up are meant to be read by computers, not people. Nevertheless, most HTML can be written and read quite easily by people. In fact, early Web page designers learned how to write HTML by looking at the markup of other people's pages.

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