function min_date(all_dates) {  
 var min_dt = all_dates[0],  
  min_dtObj = new Date(all_dates[0]);  
 all_dates.forEach(function(dt, index)  
  {  
  if ( new Date( dt ) < min_dtObj)  
  {  
  min_dt = dt;  
  min_dtObj = new Date(dt);  
  }  
  });  
 return min_dt;  
  }  
console.log(min_date(['2015/02/01', '2015/02/02', '2015/01/03']));