Javascript Date getDaySuffix()

// Gen the english suffix for dates
Date.prototype.getDaySuffix =
  function(utc) {
    var n = this.getUTCDate();
    // If not the 11th and date ends at 1
    if (n != 11 && (n + '').match(/1$/))
      return 'st';
    // If not the 12th and date ends at 2
    else if (n != 12 && (n + '').match(/2$/))
      return 'nd';
    // If not the 13th and date ends at 3
    else if (n != 13 && (n + '').match(/3$/))
      return 'rd';
    else/*  w  ww . ja va  2s .  c o  m*/
      return 'th';
  };