The variable or expression referred to is evaluated, and if it is true the DTML following the tag is rendered. If it is not true and if there is an else tag following the if tag than the DTML following the else tag will be rendered. God is in heaven and all is right with the world. The law is inside out, the world is upside down. This will be rendered in either case Note that the last line, because it comes after the closing tag, is rendered unconditionally.
Numeric values are true if they are non-zero and false if they are zero.
Objects that are sequences of objects, like search results, are true if the sequences are non-empty and false otherwise. Most other objects are true. The comment tag is used to mark comments in the DTML code. There is much more to DTML, please read the Zope Document Template Markup Language Reference for more information. Okay, let's make a new page.