validating variable in javascript

Question

Hi i have a field in php that will be validated in javascript using i.e for emails

var emailRegex = /^[\w-\.]+@([\w-]+\.)+[\w-]{2,4}$/;

What i'm after is a validation check which will look for the first letter as a capital Q then the next letters can be numbers only then followed by a . then two numbers only and then an optional letter i.e Q100.11 or Q100.11a

I must admit i look at the above email validation check and i have no clue how it works but it does ;)

many thanks for any help on this

Steve

are you looking for the regular expression to use, or the javascript, or both? — foson
– foson, Commented Mar 19, 2011 at 20:50

Lekensteyn · Accepted Answer · 2011-03-19 21:03:35Z

The ^ marks the beginning of the string, $ matches the end of the string. In other words, the whole string should exactly match this regular expression.

[\w-\.]+: I think you wanted to match letters, digits, dots and - only. In that case, the - should be escaped (\-): [\w\-\.]+. The plus-sign makes is match one or more times.
@: a literal @ match
([\w-]+\.)+ letters, digits and - are allowed one or more times, with a dot after it (between the parentheses). This may occur several times (at least once).
[\w-]{2,4}: this should match the TLD, like com, net or org. Because a TLD can only contain letters, it should be replaced by [a-z]{2,4}. This means: lowercase letters may occur two till four times. Note that the TLD can be longer than 4 characters.

An regular expression which should follow the next rules:

a capital Q (Q)
followed by one or more occurrences of digits (\d+)
a literal dot (.)
two digits (\d{2})
one optional letter ([a-z]?)

Result:

var regex = /Q\d+\.\d{2}[a-z]?/;

If you need to match strings case-insensitive, add the i (case-insensitive) modifier:

var regex = /Q\d+\.\d{2}[a-z]?/i;

Validating a string using a regexp can be done in several ways, one of them:

if (regex.test(str)) {
   // success
} else {
   // no match
}

mkruzil · Accepted Answer · 2011-03-19 21:07:16Z

1

var emailRegex = /^Q\d+\.\d{2}[a-zA-Z]?@([\w-]+\.)+[a-zA-Z]+$/;
var str = "[email protected]";
alert(emailRegex.test(str));

edited Mar 19, 2011 at 21:07

answered Mar 19, 2011 at 20:52

mkruzil

7605 silver badges11 bronze badges

2 Comments

Jared Farrish Over a year ago

I'm guessing you might also include a sample of how to use it in JS.

erlando Over a year ago

Close but not quite. It's not * but ? right before the @. Also there was no case given on the last letter, so better make it both. Lastly, 4 letters are not enought for TLDs (museum comes to mind) but they are letters only. /^Q\d+\.\d{2}[a-zA-Z]?@([\w-]+\.)+[a-zA-Z]+$/

foson · Accepted Answer · 2011-03-19 21:03:27Z

-1

var regex = /^Q[0-9]+\.[0-9]{2}[a-z]?$/;

+ means one or more

the period must be escaped - \.

[0-9]{2} means 2 digits, same as \d{2}

[a-z]? means 0 or 1 letter

You can check your regex at http://regexpal.com/

edited Mar 19, 2011 at 21:03

answered Mar 19, 2011 at 20:56

foson

10.2k2 gold badges38 silver badges53 bronze badges

3 Comments

Loki Kriasus Over a year ago

Your dot will match any symbol, not just a dot. It should be a \. instead. Also, [a-z] does not include uppercase letters.

foson Over a year ago

yeh, I see you need to code the line for the \ to show. Thanks for the downvote.

Steven Kinnear Over a year ago

Hi thanks, the reg code actually only allows one letter at the end which i was after ;) thanks foson

Collectives™ on Stack Overflow

validating variable in javascript

3 Answers 3

Comments

2 Comments

3 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

2 Comments

3 Comments

Your Answer

Sign up or log in

Post as a guest

Related