Extends the [URI][] class to add methods for computing relative and absolute urls.

Returns the absolute path for a given url (i.e. a path beginning with '/'). If a different schemes or hosts are used, it returns the full url.

myURI.toAbsolute([base]);

1. base - (mixed, optional) - either an instance of URI or a string (which will be passed to URI) that contains the base location for the path.

• string - the absolute path beginning with '/'.

Returns the relative path for a given url (i.e. a path that might include '../' for example). If a different schemes or hosts are used, it returns the full url.

myURI.toRelative([base]);

1. base - (mixed, optional) - either an instance of URI or a string (which will be passed to URI) that contains a location that is relative to myURI.

var uri1 = new URI('http://www.test.com/this/is/a/path.html');
var uri2 = new URI('http://www.test.com/this/is/an/adjacent/path.html')
uri1.toRelative(uri2); //returns "../../a/path.html"

• string - the relative path.