title: Validation for fax number in javascript using Regex
body: <p>I have one requirement wherein I have to put a validation check on fax number using Regex.The accepted characters in fax number are + . and numbers from 0 to 9. For this I have written the following javascript function </p>
  
  <pre><code>function validateFax(checkField) {
      if (checkField.value.length &gt; 0) {
          var faxRegEx = /[\+? *[1-9]+]?[0-9 ]+/;
          if (!checkField.value.match(faxRegEx)) {
              return false;
          }
      }
      return true;
  }
  </code></pre>
  
  <p>but it is not helping me to check all acceptable characters. Moreover it checks only 3 to 4 characters, but my fax number can consist of any number of characters. I am new to Regex. Can any one kindly tell me how can I modify this function to make it aligned to my requirement. Thanks in advance.</p>