What is the meaning of this code

This is a so called 'regular expression' (RegEx).
Just have a look at this :http://en.wikipedia.org/wiki/Regular_expression[^]

Your RegEx will match when:

0 or more whitespaces (\s*)
are followed by
exactly two digits (\d{2})
followed by ':'
followed by 0 or more whitespaces (\s*)
followed by
exactly two digits (\d{2})

The syntax and behaviour of regEx are depending on the underlaying regEx engine. So there are quite big differences in using regEx in Perl, PHP or C#.
So be carefull with examples from other programming languages.

Have a look at this article to get started in Regular Expression:

An Introduction to Regular Expressions[^]


hope it helps :)

this is one type of Regular expression.
You can get the different type of regular expression from the site:

http://regexlib.com/UserPatterns.aspx?authorid=0ebe8f93-b71b-4d1c-bfc2-0b583c464641[^]

Have a look at below CodeProject Articles on "Regular Expressions".

The 30 Minute Regex Tutorial

Learn Regular Expressions (RegEx) with Ease

http://www.regular-expressions.info/reference.html[^]