Use js to determine whether the current TimeZone TimeZone is daylight saving time

 
var d1 = new Date(2009, 0, 1); 
var d2 = new Date(2009, 6, 1); 
if (d1.getTimezoneOffset() != d2.getTimezoneOffset()) 
{ 
alert('Daylight Saving Time'); //Daylight saving time
} 
else 
{ 
alert('Daylight Time'); // non Daylight saving time
}