Regular Expression Allow letters numbers and spaces with at least one letter or number

Question

I m currently using this regex   A-Z0-9      to accept letters  numbers  spaces and underscores  I need to modify it to require at least one number or letter somewhere in the string  Any help would be appreciated   This would be for validating usernames for my website  I d actually like to support as many characters as I can  but just want to ensure that I prevent code injection and that characters will display fine for all users  So I m definately open to regex validation suggestions that would support a wider set of characters

User · Answer

You can use a lookaround            A-Za-z0-9   A-Za-z0-9        It will check ahead that the string has a letter or number  if it does it will check that the rest of the chars meet your requirements   This can probably be improved upon  but it seems to work with my tests     UPDATE     Adding modifications suggested by Chris Lutz              W     w

User · Answer

ValuationName   bind  keypress   function  event        if  event charCode  0            var regex   new RegExp    a-zA-Z                var key   String fromCharCode  event charCode   event which   event charCode           if   regex test key                 event preventDefault                return false

User · Answer

This will validate against special characters and leading and trailing spaces   var strString    Your String    strString match    A-Za-z0-9  A-Za-z0-9     A-Za-z0-9

User · Answer

To go ahead and get a point out there  instead of repeatedly using these    A-Za-z0-9     A-Za-z0-9    I have two  hopefully better  replacements for those two     w      W     The first one matches any word character  alphanumeric and    as well as Unicode  and the space  The second matches anything that isn t a non-word character or an underscore  alphanumeric only  as well as Unicode    If you don t want Unicode matching  then stick with the other answers  But these just look easier on the eyes  in my opinion   Taking the  preferred  answer as of this writing and using the shorter regexes gives us      w      W    w       Perhaps more readable  perhaps less  Certainly shorter  Your choice   EDIT   Just as a note  I am assuming Perl-style regexes here  Your regex engine may or may not support things like  w and  W   EDIT 2   Tested mine with the JS regex tester that someone linked to and some basic examples worked fine  Didn t do anything extensive  just wanted to make sure that  w and  W worked fine in JS   EDIT 3   Having tried to test some Unicode with the JS regex tester site  I ve discovered the problem  that page uses ISO instead of Unicode  No wonder my Japanese input didn t match  Oh well  that shouldn t be difficult to fix    lt meta http-equiv  Content-Type  content  text html  charset utf-8  gt    Or so  I don t know what should be done as far as JavaScript  but I m sure it s not hard

User · Answer

Simply u can add this to jquery validationEngine-en js file           onlyLetterNumberSp                      regex     A-Za-z0-9     A-Za-z0-9  A-Za-z0-9                        alertText      No special characters allowed                 and call it in text field as    lt input type  text  class  form-control validate required custom onlyLetterNumberSp     id  title  name  title  placeholder  Title   gt

User · Answer

for me      w       is working  allow number  alphabet and space  but need to type at least one letter or number

User · Answer

A-Z0-9  A-Z0-9        You can optionally have some spaces or underscores up front  then you need one letter or number  and then an arbitrary number of numbers  letters  spaces or underscores after that   Something that contains only spaces and underscores will fail the  A-Z0-9  portion

User · Answer

You simply need to specify your current RE  followed by a letter number followed by your current RE again     A-Z0-9     A-Z0-9  A-Z0-9        Since you ve now stated they re Javascript REs  there s a useful site here where you can test the RE against input data   If you want lowercase letters as well     A-Za-z0-9     A-Za-z0-9  A-Za-z0-9

[javascript] Regular Expression: Allow letters, numbers, and spaces (with at least one letter or number)

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