Phone number Regular Expression Validators

Posted on 2010-09-20
Last Modified: 2012-05-10
Hi There

I am trying to force a user to insert a number in a specified format.

Our cell numbers in south africa is in the following format
I need them to write the number as

I currently have a kasked extender that works like this
<ajaxToolkit:MaskedEditExtender runat="server" ID="mee" ClearMaskOnLostFocus="false" TargetControlID="txtCell" Mask="+27999999999"></ajaxToolkit:MaskedEditExtender>

But the users are still entering the nu,mbers incorrectly.

I need a regular expression that there is no 0 after the 27 and that the amount of digits is 11 exluding the +


Question by:Stanton_Roux
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Expert Comment

ID: 33715786
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.

LVL 13

Expert Comment

ID: 33715852
you can use the asp:regular expression control.

Here is the regex you are looking for:



LVL 14

Expert Comment

by:Dushyant Sharma
ID: 33715862
You can try this
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Accepted Solution

käµfm³d   👽 earned 500 total points
ID: 33716008
This pattern should suit you:

Open in new window

LVL 31

Expert Comment

by:Marco Gasi
ID: 33716079
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:

$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;
LVL 13

Expert Comment

ID: 33716331
I misread your question, I thought you wanted 11 including the + not excluding..

Modification of my previous post:

LVL 75

Expert Comment

by:käµfm³d 👽
ID: 33717334

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:

Open in new window

LVL 13

Expert Comment

ID: 33717370
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?

LVL 75

Expert Comment

by:käµfm³d 👽
ID: 33717483
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.
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Expert Comment

ID: 33717502
Ah I see. ok cool thanks.

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