Here I list 2 very useful pdf documents for quick referring purpose:

1. jquery_selectors card (6 pages)

   • Basic CSS selectors
   • Positional selectors
   • Custom jQuery selectors
   • Matched Set Methods
   • Controlling Chaining

2. Regular Express sheet (1 page)

   • Anchors
   • Character Classes
   • POSIX Character Classes
   • Assertions
   • Sample Patterns
   • Quantifiers
   • Special Characters
   • String Replacement(Backreferences)
   • Ranges
   • Pattern Modifiers
   • Metacharacters

The RE is compatible in PHP, Perl, Python, and Ruby, so it’s worth to reserve.