Validate 11 Digits in JavaScript

Question

Might be a simple question, but I can't find an answer that fits this bit of code :(

I need to validate a phone number to have EXACTLY 11 digits (no letters)

    function validateForm3() {
  var x=document.forms["booking"]["number"].value;
if (x==null || x=="")
  {
  alert("Please fill in 11 numbers");
  return false;
  }
   var x=document.forms["booking"]["email"].value;
if (x.indexOf("@")=== -1)
  {
  alert("Please enter a valid email");
  return false;
  }
}

I can't really change the structure of this, so it needs to fit into this bit of code :( any suggestions or answers is greatly appeciated :)

Answer 1

Use regexp.test:

if (! /^[0-9]{11}$/.test(x)) {
  alert("Please input exactly 11 numbers!");
  return false;
}

Note that you're intentionally excluding a lot of phone numbers, including international ones or alternative writing styles of phone numbers you could reach. You should really just test for /^\+?[0-9]+$/.

Answer 2

if (!/^\d{11}$/.test(x)) 
    alert('These are not 11 digits!');
else 
    alert('Passed!');

Try it http://jsfiddle.net/LKAPN/1/

Answer 3

Use regex:

"1234".match(/^\d{4}$/);

Explanation:

^   - matches the beginning of the string
\d  - matches one digit
{4} - tells that we want four digits (you want thirteen then)
$   - matches the end of the string

See https://developer.mozilla.org/en/JavaScript/Guide/Regular_Expressions for further reading.