Validating Uk Phone Numbers

[konfused]

In my registration form I filter the UK phone number as follows:

// Has a phone number been entered?    
if (!empty($_POST['phone'])) {            
//Remove spaces, hyphens, and brackets.
$phone=str_replace(array(' ', '-', '(', ')', ')'), '',$_POST['phone']);}//line 212
//Use regex to check that the remaining characters are digits
If (preg_match('/^[0-9]{11}$/', $phone)){
$ph=$phone;
}
else{
$errors[]= 'Phone numbers may only contain spaces, brackets, hyphens and the digits 0 to 9, please correct it';
}
if (empty($_POST['phone'])){
$ph=NULL;
}

If the number is entered by the user it registers without a problem.
If a letter is inserted among the numbers it displays the error message correctly .
If a space is inserted it displays the error message, but it shouldn't
The phone field is set at NULL in the table because some users are ex-directory and prefer not to declare their phone numbers.
However, if the field is empty it displays the error message, but it shouldn't, and it also puts up a notice: "Undefined variable in line 212".

1. Please would tell me how to correct the code.

2. Some UK numbers have 10 digits, how do I allow that?

[margaux]

Try declaring

$phone = '';

before the first if statement.

 

You may want to double check your regex because I did not get the results you described. Also check that you are using null and empty correctly as they do not always equate.

 

Finally - please use code tags for your code.

[HartleySan]

konfused, if you want to filter all non-digits out of a phone number, use the following regex replace:

 

 

$new_str = preg_replace('/\D+/', '', $old_str);

 

This will remove ALL non-digit characters from the string. From there, you should be able to do any testing that is necessary.

[konfused]

Thank you Margaux and HartleySan

 

Adding $phone = ''; did not improve things. I used HarleySans suggestion and that resolved the issue.

 

I don't understand what you mean by "use code tags", I did use tags, do you mean that I should change all tags to entities before submitting a query?

 

regards

Konfused

[Antonio Conte]

Jon: Did not know that. Thanks for the snippet.

 

konfused: As in the forum's code tags. They'll format code for you. Look for the "<>" symbol.

 

Look at this:

// Has a phone number been entered?    
if (!empty($_POST['phone'])) {            
   //Remove spaces, hyphens, and brackets.
   $phone=str_replace(array(' ', '-', '(', ')', ')'), '',$_POST['phone']);} //line 212

   //Use regex to check that the remaining characters are digits
   If (preg_match('/^[0-9]{11}$/', $phone)){
      $ph=$phone;
   }
}

 

Versus this:

 

// Has a phone number been entered?    
if (!empty($_POST['phone'])) {            
//Remove spaces, hyphens, and brackets.
$phone=str_replace(array(' ', '-', '(', ')', ')'), '',$_POST['phone']);}//line 212
//Use regex to check that the remaining characters are digits
If (preg_match('/^[0-9]{11}$/', $phone)){
$ph=$phone;
}

[konfused]

Thanks to everyone.

Using Hartley San's digits-only solution solved the problem for USA and UK phone numbers.

I can now see the "<>" symbol and will use it in future.