function strpbrk (haystack, char_list) {
  // http://kevin.vanzonneveld.net
  // +   original by: Alfonso Jimenez (http://www.alfonsojimenez.com)
  // +   bugfixed by: Onno Marsman
  // +    revised by: Christoph
  // +    improved by: Brett Zamir (http://brett-zamir.me)
  // *     example 1: strpbrk('This is a Simple text.', 'is');
  // *     returns 1: 'is is a Simple text.'
  for (var i = 0, len = haystack.length; i < len; ++i) {
    if (char_list.indexOf(haystack.charAt(i)) >= 0) {
      return haystack.slice(i);
    }
  }
  return false;
}

strpbrk('This is a Simple text.', 'is');

'is is a Simple text.'