regular expression tutorial
http://code.tutsplus.com/tutorials/you-dont-know-anything-about-regular-expressions-a-complete-guide--net-7869
http://ahkscript.org/docs/misc/RegEx-QuickRef.htm
http://www.9lessons.info/2009/03/perfect-javascript-form-validation.html
good js validation examples with some regular expressions
http://www.w3resource.com/javascript/form/javascript-validation-download.php