C# Regex does not work in Javascript, MVC4, Custom RegularExpressionAttribute, IClientValidatable

Question

I have a custom regular expression attribute which implements IClientValidate so that I can use it with unobtrustive validate.

When I run it I get the following error in FireBug

SyntaxError: Invalid quantifier
match = new RegExp(params).exec(value);

It obviously does not like the regular expression that is passed to it, it is valid in C#. I can't seem to work out what I need to do to get it to be valid in JavaScript.

The regex is

^(?i)([A-PR-UWYZ0-9][A-HK-Y0-9][AEHMNPRTVXY0-9]?[ABEHMNPRVWXY0-9]?\s?[0-9][ABD-HJLN-UW-Z]{2})$

Answer 1

The JavaScript regex flavor is extremely limited compared to .NET (C#). One of the many features it doesn't support is inline modifiers of the form (?i)regex or (?i:regex). However, because you're using the new RegExp(params) constructor, you should be able to pass the modifier as the second parameter:

"^[A-PR-UWYZ0-9][A-HK-Y0-9][AEHMNPRTVXY0-9]?[ABEHMNPRVWXY0-9]?\s?[0-9][ABD-HJLN-UW-Z]{2}$",
"i"

Answer 2

Replace (?i) by i modifier:
var patt=/^([A-PR-UWYZ0-9][A-HK-Y0-9][AEHMNPRTVXY0-9]?[ABEHMNPRVWXY0-9]?\s?[0-9][ABD-HJLN-UW-Z]{2})$/i

Answer 3

When i run your regex in this : http://regexpal.com/ I get error on this part : (?i)

Rexegpal is a JavaScript regular expression tester. So if you can get it to work here you can then apply it in your code.

Perhaps you have some example string to try with?