date.js

  $.each(
    {
      Y: 'FullYear',
      m: 'Month',
      d: 'Date',
      D: 'Day',
      H: 'Hours',
      M: 'Minutes',
      S: 'Seconds',
      s: 'Milliseconds',
      t: 'Time'
    },
    function(k, v){
      Date.prototype[k] = 
        (function(s,g){
          return function(v) {
            if (v!==undefined) {
              this[s](v);
              return this;
            } else {
              return this[g]();
            }
          }
        })('set' + v, 'get' + v);
    }
  );
  Date.prototype.fmt = function(s){
    var d = this;
    
    function x(m) {
      var v = d[m]();
      (m == 'm') && v++;
      
      ('mdHMS'.indexOf(m) > -1) && (v < 10) && (v = '0' + v);
      
      return v;
    }
    
    return s.replace(/%./g, function(m){
      m = m.charAt(1);
      
      return m=='%' ? m :
          m in d ? x(m) :
          '*';
    });
  };