title: Regex to validate 13 digit telephone number is numeric and can contain maximum of 3 spaces
body: <p>I would like to validate a telephone number which can contain 10 to 13 digit numbers and can contain 0 to 3 spaces (can come anywhere in the data). Please let me know how to do it?</p>
  
  <p>I tried using regex <code>^(\d*\s){0,3}\d*$</code> which works fine but I need to restrict the total number of characters to 13. </p>