var is_date = function(input) {  
  if ( Object.prototype.toString.call(input) === "[object Date]" )   
    return true;  
  return false;     
    };  
  
console.log(is_date("October 13, 2014 11:13:00"));  
console.log(is_date(new Date(86400000)));  
console.log(is_date(new Date(99,5,24,11,33,30,0)));  
console.log(is_date([1, 2, 4, 0]));