Question

I have a string that holds user input. This string can contain various types of data, like:

• a six digit id
• a zipcode that contains out of 4 digits and two alphanumeric characters
• a name (characters only)

As I am using this string to search through a database, the query type is determined on the type of search, which i want to handle serverside using JavaScript (yes, I am using JavaScript serverside). Searching on StackOverflow, brought me some interesting information, like the .test-method, which seems perfect for my needs. The test-method returns either true or false based on the evaluation on the string using a regex object.

I am using this page as a reference:
http://www.javascriptkit.com/jsref/regexp.shtml

So I am trying to determine the zipcode, by using the following very noobish regex.

var r = /[A-Za-z]{2,2}/

As far I can understand, this should limit the amount of occurrences of alphanumeric characters to a maximum of two. See beneath the output of my JavaScript console.

> var r = /[A-Za-z]{2,2}/
> var x = "2233AL"
> r.test(x)
true
> var x = "2233A"
> r.test(x)
false
> var x = "2233ALL"
> r.test(x)
true  /* i want this to be false */
> 

A little help would be really appreciated!

Answer 1

/([^a-z]|^)[a-z]{2}([^a-z]|$)/i

part 1: ([^a-z]|^) … no letter or start of the string

part 2: [a-z]{2} … two letters

part 3: ([^a-z]|$) … no letter or end of the string

/i … case insensitive