Date.longMonths = ['January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December'];  
  
function full_month(dt)  
  {   
   return Date.longMonths[dt.getMonth()];   
  }  
  
dt = new Date();   
console.log(full_month(dt));   
  
dt = new Date(2015, 10, 1);   
console.log(full_month(dt));  