o URL starts with a-z, A-Z (e.g. http, ftp...)
o It is then followed by ://
o next we have more letters, numbers and special chars : a-z, A-Z, 0-9, -, _
o there must be at least one "."
o A URL can contain at it's end part the more special characters and this is
why the last part allows for more options such as ?, /, &, %, etc...
you may add/remove chars as needed to your code.
*/
// Assuming that the URL is received from a FORM by POST with the field name being "URL" the code
// Looks like this :
if(!preg_match("/^[a-zA-Z]+[:\/\/]+[A-Za-z0-9\-_]+\\.+[A-Za-z0-9\.\/%&=\?\-_]+$/i",$_POST[URL])) {
Echo"You must supply a valid URL.";
Exit();
}
?>
[code]