You can add a variable prefix to all the available variables below by adding the following to your config.php file:
$config['url_helper']['prefix'] = 'url:';
check to see if the current page was requested via ajax.
returns the very last segment in the URI, even if it's a pagination segment
returns the very last segment in the URI, but 2nd to last if the last is a pagination segment
returns the ID of the last segment, in the case of /seg1/seg2/seg3/ it will return "3"
return the ID of the last segment, or 2nd to last if the last is a pagination segment. In the case of ### /seg1/seg2/seg3/P5 it will return "3"
Will return the 2nd to last segment in the URI. In the case of /seg1/seg2/seg3/, it will return "seg2"
returns the ID of the 2nd to last segment, in the case of /seg1/seg2/seg3/ it will return "2"
returns the 2nd to last segment in the URI, but 3rd to last if the last is a pagination segment
return the ID of the 2nd to last segment, or 3rd to last if the last is a pagination segment. In the case of ### /seg1/seg2/seg3/P5 it will return "2"
seg1/seg2/seg3 - Will return seg1/seg2
seg1/seg2/seg3
http://www.mysite.com + segments + query string
http://www.mysite.com + segments
segments + query string
{current_url} base64encoded
{current_uri} base64encoded
current query string including ?, returns blank if no query string exists
full referring/previous url visited
fetch any segment from the referring url
segments reversed
2&6&9 - useful for doing an all inclusive search of the segments
2|6|9 - useful for doing an "if any" search of the segments
current query string without ?
http, https, ftp etc
your domain name, e.g. localhost, site.com
any port number present in the URL, e.g. :80 or :8888
full folder/virtural folder path or all segments if your site is located at the root of the domain/vhost
anything after # in the URI