Javascript Date DiffInDays(date)

Date.prototype.DiffInDays = function (date) {
 if(date instanceof Date && !isNaN(date.getTime())) {
  var cDate = this.getTime();
  var tDate = date.getTime();
  
  var resultMillis = Math.abs(cDate - tDate);
  
  var result = resultMillis / 1000 / 60 / 60 / 24;
  
  return result;/*w ww  .java2s  . c o m*/
 } else {
  console.error(date, " is not a valid date.")
 }
}