Description of problem:
I opened this bug some time ago in opensuse bugzilla, with no luck. Now i want to repropose it here, the problem still persist on linux systems after many years.
Some web site checks the validity of the date provided in a form using JavaScript performing a "tmp =
new Date (form_year, form_month-1, form_day)" and then checking whether
"form_year = tmp.getYear()" and so on.

This induces a wrong answer for some dates where DST occurred (format:
dd/mm/yyyy): 22/05/1966, 28/05/1967, 01/06/1969, 31/05/1970, 23/05/1971,
28/05/1972, 03/06/1973, 26/05/1974, 01/06/1975, 30/05/1976, 22/05/1977,
28/05/1978, 17/05/1979.

For instance, a "new Date(1972, 4, 28)" returns "May 27 1972, 23:00:00 GMT+0100
(CET)" instead of the correct date "May 28 1972...".

The point in common for all these dates is that the DST change happened at
00:00:00.
However there are other dates where the DST change happened at 00:00:00 that do
not induce the above error: 04/06/1916, 01/04/1917, 10/03/1918, 02/03/1919,
21/03/1920, 15/06/1940, 16/03/1947, 26/05/1968.

For all remaining years, either there was no DST change or it happened at a
time different from 00:00:00 (usually 02:00:00).

I performed the above tests using the addon FireBug and adding a "new
Date(...)" watch.

This problem occurs in Firefox as well as Chrome but not in Opera and
Konqueror, accordingly to reports from forum users.
Moreover, the same happens for other distributions (Mandriva, Fedora, Ubuntu)
but not on Windows (with the same version of Firefox, for instance), so it
seems to be something independent from the browser and OS but dependent on an
element that is common for several Linux distributions, such as the timezone
package.

If I zdump the Europe/Rome timezone relative to years 1972 (where error occurs)
and 1968 (where error does not occur), the result is essentially the same:

orodruin:/home/ori # zdump -v Europe/Rome|grep 1968
Europe/Rome  Sat May 25 22:59:59 1968 UTC = Sat May 25 23:59:59 1968 CET
isdst=0
Europe/Rome  Sat May 25 23:00:00 1968 UTC = Sun May 26 01:00:00 1968 CEST
isdst=1
Europe/Rome  Sat Sep 21 21:59:59 1968 UTC = Sat Sep 21 23:59:59 1968 CEST
isdst=1
Europe/Rome  Sat Sep 21 22:00:00 1968 UTC = Sat Sep 21 23:00:00 1968 CET
isdst=0
orodruin:/home/ori # zdump -v Europe/Rome|grep 1972
Europe/Rome  Sat May 27 22:59:59 1972 UTC = Sat May 27 23:59:59 1972 CET
isdst=0
Europe/Rome  Sat May 27 23:00:00 1972 UTC = Sun May 28 01:00:00 1972 CEST
isdst=1
Europe/Rome  Sat Sep 30 21:59:59 1972 UTC = Sat Sep 30 23:59:59 1972 CEST
isdst=1
Europe/Rome  Sat Sep 30 22:00:00 1972 UTC = Sat Sep 30 23:00:00 1972 CET
isdst=0

so timezone seems to be innocent.

Version-Release number of selected component (if applicable):


How reproducible:
see above


Additional info:

happen on all linux distributions i have tried. This is very annoying bug , for example i cannot enter on my bank account with firefox or chrome because of the failed verification of my birth date. ABSURD! 
No problem on firefox for windows or with opera.