Question

I am using ASP.Net MVC to validate that a string will not contain more than 2 numbers in any form.

I’m using the following server side code:

[RegularExpression(@"[^\d]*\d?[^\d]*\d?[^\d]*",ErrorMessage = "More than 2 Numbers are not allowed")]

That works great, but the following JavaScript code will always return 0:

>> var mystring = "test123"; 
>> var myregax = new RegExp("[^\d]*\d?[^\d]*\d?[^\d]*"); 
>> mystring.search(myregax); 
0 
>> mystring = "test"; 
"test" 
>> mystring.search(myregax); 
0 

What am I missing and what is the difference between the regular expression syntax of ASP.Net and JavaScript?

Answer 1

Using RegExp object you have to escape the \ in your pattern

new RegExp("[^\\d]*\\d?[^\\d]*\\d?[^\\d]*"); 

or, as alternative, use this syntax

var myregax = /[^\d]*\d?[^\d]*\d?[^\d]*/;