From abroad, to call a UK number you need to drop the leading zero and prefix with the dialing code 44: Thankfully, there is a format we can use which enable us to get around these variations.
It was probably a decade before signage was changed across the country to reflect the changes.
Then, of course, there was the enormous and unprecedented growth in mobile.
For example, to find out whether a given dialing code is valid: There are a more efficent ways of doing this, of course, so this and the following examples aren’t necessarily optimized for production.
We can look up the countries which use a particular dialing code: /** * Gets the dialing codes for a given country * * @param string country The two-character country code * @return array An array of strings representing the dialing codes */ get Codes : function(country) You’ll find these functions packaged up as a module, along with unit tests, in the repository that accompanies the article.
However, it’s one thing to annoy users by making assumptions – asking a non-US user to provide a state and a zip-code.
It’s quite another to make a form completely unusable, for example by forcing people to provide numbers in a certain country’s format.There isn’t necessarily a one-to-one mapping; 44 for example, is used not just for the United Kingdom but for the Isle of Man, Guernsey and Jersey.Numbers must also be altered according to where you’re dialing from.Even international dialing codes, however, aren’t as straightforward as you may think.The format can vary – 1, 43, 962 1868 are all valid codes.Names aren’t as straightforward as they sound, but provided you cater for edge cases and international variations – for example patronymics, the mononymous, or even just people with hyphenated surnames – you can’t go too far wrong (although plenty of applications and services do! Email addresses, while theoretically very easy to validate, have their own challenges – yet nevertheless, there are plenty of regular expressions in the wild that aren’t quite right. All sorts of external factors can have implications for telephone numbering.