Validate Telephone # Entry

[webpro]

hi,

I have a required telephone form field that i wish to validate as
a) required and b) contains only numbers.

problem I am having is that it is an international form so ppl will use different ways of entering the telephone eg:

USA: 111-111-1111
111-111-1111

[webpro]

Ignore above post, page was submitted b4 i had finnished doing the message LOL

hi,

I have a required telephone form field that i wish to validate as
a) required and b) contains only numbers.

problem I am having is that it is an international form so ppl will use different ways of entering the telephone eg:

USA: 111-111-1111
111-111-1111
UK: 0113 000 0000
0113-111-1111
and so on........

I use the following is numeric check but if there are spaces or dashes in the telephone number then it fails....

if (!$telephone) {
  $error = 1;
  $errstring .= "<li>+ Please enter your contact telephone number.</li> "; 
} elseif ($telephone) { 
  if (!is_numeric($telephone)){
	$error = 1;
	$errstring .= "<li>+ The entered Telephone Number contains letters. - Use numbers only<BR></li>"; 
  }
 } 

are there any functions i can use to check its a number while accounting for spaces and hashes between the numbers

many thanks
webpro