Regular expression for validating numbers only
Enclosing the expression in the caret (^) and dollar sign ($)markers ensures that the expression consists of the desired content and nothing else.A ^ matches the position at the beginning of the input string and a $ matches the position at the end of the input string.DOTALL is a flag in most recent regex libraries that makes the . There is no 100% reliable solution since the RFC is way too complex. ] )*@([a-z0-9_][-a-z0-9_]*(\.[-a-z0-9_] )*\.(aero|arpa|biz|com|coop|edu|gov|info|int|mil|museum|name|net|org|pro|travel|mobi|[a-z][a-z])|([0-9]\.[0-9]\.[0-9]\.[0-9]))(:[0-9])? $ This will make sure that every number in the IP address is between 0 and 255, unlike the version using \d which would allow for 999.999.999.999.metacharacter match anything INCLUDING line breaks. Java Script by default does not support this since the . This is the best solution and should work 99% of the time is. If you want to match an IP within a string, get rid of the leading ^ and trailing $ to use \b (word boundaries) instead. The regular expression is only useful to validate the format of the date as entered by a user.To validate a server control's input using a Regular Expression Validator The regular expression used in the preceding code example constrains an input name field to alphabetic characters (lowercase and uppercase), space characters, the single quotation mark (or apostrophe) for names such as O'Dell, and the period or dot character.
The following expressions will validate the number of days in a month but will NOT handle leap year validation; hence february can have 29 days every year, but not more. A SIN should also be validated by computing the checksum digit.You can use them to constrain input, apply formatting rules, and check lengths. This How To shows how you can use regular expressions within ASP. Objectives Overview Using a Regular Expression Validator Control Using the Regex Class Common Regular Expressions Additional Resources If you make unfounded assumptions about the type, length, format, or range of input, your application is unlikely to be robust.To validate input captured with server controls, you can use the Regular Expression Validator control. Input validation can become a security issue if an attacker discovers that you have made unfounded assumptions.This free regular expression tester lets you test your regular expressions against any entry of your choice and clearly highlights all matches.It is Java Script based and uses XReg Exp library for enhanced features.