Date.longDays = ['Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday'];  
  
function long_Days(dt)  
    {   
      return Date.longDays[dt.getDay()];   
    }  
  
dt = new Date();  
console.log(long_Days(dt));  
  
dt = new Date(2015, 10, 1);  
console.log(long_Days(dt));