HyperText Markup Language/To Do

To Do

 * Discuss COLGROUP and COL, Tables.
 * Show how to place images using CSS, in Images.
 * Discuss aspect ratio of width and height in case that only one of the two is specified, in Images.
 * Show how to embed images directly into HTML, in Images.
 * List image types (JPEG, PNG) typically supported by browsers, in Images.
 * Treat SPAN and DIV elements.
 * Clean up and rewrite the Hyperlinks chapter. The order of parts seems to be confused.
 * Cover DOCTYPE
 * Cover CODE