DTD - DOCTYPE Definition
Rules:
| 1) Declare a DOCTYPE | <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict //EN" "html://www.w3.org/TR/xhtml1/DTD/html1-strict.dtd"> | Transitional or Frameset |
| 2) Declare an XML namespace | <html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml: lang="en"> | |
| 3) Declare your content type | <meta http-equiv="Content-type" content="text/thml;charset=iso-8859-1" | |
| 4) Close every tag | <p>This is paragraph of text inside paragraph tags</p> | |
| 5) Tags must be nested correctly | <p>It's <strong>very important</strong> to nest tags correctly</p> | |
| 6) Inline tags can't contain block level tags | ||
| 7) Write tags entirely in lowercase | ||
| 8)Attributes must have values and must be quoted | ||
| 9) Use the encoded equivalents for a left angle bracket and ampersand within a content |