(PHP 5 >= 5.1.0)
date_default_timezone_get — Gets the default timezone used by all date/time functions in a script
This functions returns the default timezone, using the following "guess" order:
The timezone set using the date_default_timezone_set() function (if any)
The TZ environment variable (if non empty)
The date.timezone ini option (if set)
"magical" guess (if the operating system supports it)
If none of the above options succeeds, return UTC
Returns a string.