As We all Know that RegEx (Regular Expressions) is Leading Validation Technique Used in Many of Web,RUI.. application development, I just Like to provide a brief on it.

Here it follows
Regular Expression Will match…
txt The string “txt”
^txt “txt” at the start of a string
txt$ “txt” at the end of a string
^txt$ “txt” when it is alone on a string
[abc] a, b, or c
[a-z] Any lowercase letter
[^A-Z] Any character that is not a uppercase letter
(gif|jpg) Matches either “gif” or “jpeg”
[a-z]+ One or more lowercase letters
[0-9\.\-] Any number, dot, or minus sign
^[a-zA-Z0-9_]{1,}$ Any word of at least one letter, number or _
([wx])([yz]) wy, wz, xy, or xz
[^A-Za-z0-9] Any symbol (not a number or a letter)
([A-Z]{3}|[0-9]{4}) Matches three letters or four numbers