1. Http CookieA Ruby library to handle HTTP cookies in a way both compliant with RFCs and compatible with today's major browsers
2. NokogiriNokogiri (鋸) makes it easy and painless to work with XML and HTML from Ruby.
4. MechanizeMechanize is a ruby library that makes automated web interaction easy.
5. csspoolCSSPool is a CSS SAC parser and by default will output a DOM Level 2 style tree.