Date.prototype.yyyymmddhhmmss = function() {

   var yyyy = this.getFullYear().toString();

   var MM = (this.getMonth()+1).toString(); // getMonth() is zero-based

   var dd  = this.getDate().toString();

   var hh = this.getHours().toString();

   var mm = this.getMinutes().toString();

   var ss = this.getSeconds().toString();

  return yyyy + '-' + (MM[1]?MM:"0"+MM[0]) + '-' + (dd[1]?dd:"0"+dd[0]) + ' ' + (hh[1]?hh:"0"+hh[0]) + ':' + (mm[1]?mm:"0"+mm[0]) + ':' + (ss[1]?ss:"0"+ss[0]);

};

​

alert(new Date().yyyymmddhhmmss());