Javascript Date getLocalTotalPassedDays()

Date.prototype.getLocalTotalPassedDays = function() {
 /**//www.j  a v  a 2  s  .  c  om
  * for each GMT javascript Date object consider new day beginning from -GMT
  * so for enforce Date count days starting from midnight day calculation
  * must be shifted for GMT
 */
 return Math.floor((+this - this.getTimezoneOffset() * 60 * 1000) / 864e5);
};