1310806 - getTimezoneOffset incorrect during DST

Status: RESOLVED INVALID

(Core :: JavaScript Engine, defect)

Description

[alajohnny0109]

+++ This bug was initially created as a clone of Bug #173431 +++

User-Agent:       Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; .NET CLR 1.0.3705)
Build Identifier: Mozilla/1.2a

getTimezoneOffset is returning 300 in the Eastern Time Zone during daylight 
savings time.

The ECMA specs state:

15.9.5.22 Date.prototype.getTimezoneOffset()
Returns the difference between local time and UTC time in minutes.

1. Let t be this time value.
2. If t is NaN, return NaN.
3. Return (t - LocalTime(t)) / msPerMinute.

By these specs, Mozilla is returning the wrong offset -- it should be returning 
240.. or 4 hours offset during DST, and not 300 or 5 hours (which would be 
correct in non-DST).

Opera and IE (hiss) both return 240.

Reproducible: Always

Steps to Reproduce:
1. offset = getTimezoneOffset();
2. window.alert(offset);
Actual Results:  
300

Expected Results:  
240

Comment 1

[André Bargull [:anba]]

Please use https://landfill.bugzilla.org/ for testing bugzilla.