function daylights_savings(dt)   
{   
  var dst = null;  
  for (var i = 0; i < 12; ++i)   
    {  
      var d = new Date(dt.getFullYear(), i, 1);  
      var offset = dt.getTimezoneOffset();  
  
      if (dst === null)   
        dst = offset;  
      else if (offset < dst)   
         {  
           dst = offset;   
           break;  
         }   
      else if (offset > dst)   
        break;  
         }  
return (dt.getTimezoneOffset() == dst) | 0;  
}  
  
dt = new Date();   
console.log(daylights_savings(dt));   
  
dt = new Date(1989, 10, 1);   
console.log(daylights_savings(dt));