An HTML editor, which may be a text editor.
At the top of your XHTML document, you must include the “DOCTYPE” and XML namespace attributes, such as:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
< html xmlns="http://www.w3.org/1999/xhtml">
<html>, <head>, <title>, and
<body> HTML tags must be included in the page.
Nesting order of elements may not be rearranged. Each HTML element/tag must also have a closing tag.
HTML tags must also be lowercase, such as:
There can only be one root <html> tag.
Attributes within HTML tags must also be lowercase and quoted such as:
Attributes must also be fully formatted like the above <div> element, they cannot be minimized such as: