Result is the remainder of the "string" parameter, where the first occurrence of the substr parameter defines the start characters; the remainder of the string is the result of the function. An empty string is the result, if substr does not occur in string.
E.g. substring-after("2009/01/04","/") results in the substring 01/04. substr in this case is the first "/"character.
For an example of usage, see Example: Mapping Data from an RSS Feed.