Phone number Regular Expression Validators

A couple of points:
1 - you can't do that with Microsoft's ajax toolkit - the format descriptors aren't rich enough to define something as being 1-9 (and not 0).  You'd get closer with "\+\2\799999999", but this still wouldn't stop people entering +240...
2 - the masked edit extender relies on javascript.  If a user's browser doesn't have javascript, or the user has disabled it, then you get no mask applied anyway.

You'd do better letting your users enter a number in a way that makes sense to /them/, and then parsing the number to get the format /you/ want.  You could do this client-side with javascript, but as per note 2 above you'd have to be able to do it server side as well for non-javascript browsers.

Jon

you can use the asp:regular expression control.

Here is the regex you are looking for:

"^[+][2][7][1-9]{8}$"

CPG

You can try this
 \+27[0-9]{9}

I agree with jon47: let your user type phon number as they wish, post the form and receiving the form formta number as you wish.
Using php you can do this way:

<?php
$phone_number = $_POST['phone_number'];
//$phone_number = "0845678890";
$phone_number = preg_replace("/\b0/", "", $phone_number);
$phone_number = "+27".$phone_number;
if (strlen($phone_number)>12){
    echo "Invalid phone number.";
}else echo $phone_number;
?>

I misread your question, I thought you wanted 11 including the + not excluding..

Modification of my previous post:

"^[+][2][7][1-9]{9}$"

@copyPasteGhost

It's a bit redundant to put a single character in a character class--just have the character as the pattern itself. Also, your pattern is omitting zero as a valid number in the phone number. Only the first digit after "27" is not supposed to be zero, unless I am reading the question wrong  :)

I guess in hindsight, the lookahead wasn't really necessary in my post. The pattern could simply be:

^\+27[1-9]\d{8}$

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Thanks kaufmed. RegEx is something I'm trying to brush up on. (thus why i'm trying to participate is these kind of questions more.

what does
^\+27 mean?

I know ^ is the beginning of the line.

but what does the \ before "+27" do?

thanks.
CPG

Plus (+) is a special character in regex (one-or-more). Since you want to find a literal plus, you have to escape it in the pattern. That is what the backslash does. You don't need to escape it inside of a character class, though, so your usage of it was OK.

Ah I see. ok cool thanks.