function ucwords (str) {
  // http://kevin.vanzonneveld.net
  // +   original by: Jonas Raoni Soares Silva (http://www.jsfromhell.com)
  // +   improved by: Waldo Malqui Silva
  // +   bugfixed by: Onno Marsman
  // +   improved by: Robin
  // +      input by: James (http://www.james-bell.co.uk/)
  // +   improved by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
  // *     example 1: ucwords('kevin van  zonneveld');
  // *     returns 1: 'Kevin Van  Zonneveld'
  // *     example 2: ucwords('HELLO WORLD');
  // *     returns 2: 'HELLO WORLD'
  return (str + '').replace(/^([a-z\u00E0-\u00FC])|\s+([a-z\u00E0-\u00FC])/g, function ($1) {
    return $1.toUpperCase();
  });
}

ucwords('kevin van  zonneveld');

'Kevin Van  Zonneveld'

ucwords('HELLO WORLD');

'HELLO WORLD'