# Choosy Help: Web address rules

You can create advanced behaviour rules that are triggered by clicking on a link to a web address that matches certain criteria.

The following types of web address matching are availble:

is
  Matches the whole URL exactly. Note that this includes the protocol at the start of the URL (e.g. http:// or https://)
is not
  Matches any URL that is not exactly the same as the URL defined in the rule. Note that this includes the protocol at the start of the URL (e.g. http:// or https://)
contains
  Matches any URL that contains the string defined in the rule. For example, if the rule was “contains facebook” matching addresses would include http://www.facebook.com/ and http://example.com/facebook
begins with
  Matches any URL that begins with the string defined in the rule. Note that this includes the protocol at the start of the URL (e.g. http:// or https://). For example, if the rule was “begins with http://www.google.” matching addresses would include http://www.google.com/, http://www.google.co.uk/ and http://www.google.com/search?q=choosy
ends with
  Matches any URL that begins with the string defined in the rule. For example, if the rule was “ends with .pdf” it would match any direct links to PDF files.
is like
  This type of address matching allows you to define simple patterns using wildcard characters.

  Character | Matches | Example
  --- | --- | ---
  ? | Any single character | The pattern a?c would match abc but not ac or abbc
  * | Zero or more characters | The pattern a*c would match ac, abc and abbc

matches regular expression
  This type of address matching allows you to define complex patterns using regular expressions. If you are not already familiar with regular expressions there are various websites with indepth tutorials, several of which are links from the Wikipedia article on regular expressions. Choosy uses the ICU version of regular expressions, you can find documentation on the ICU project website.