/**
 * 计算时区的时差
 *
 * @author 编程之家 jb51.cc jb51.cc
 * @param string $remote_tz 远程时区
 * @param string $origin_tz 标准时区
 *
 */
function getTimeZoneOffset($remote_tz,$origin_tz = 'UTC') {
 if ($origin_tz === null) {
  if (!is_string($origin_tz = date_default_timezone_get())) {
   return false; // A UTC timestamp was returned -- bail out!
  }
 }
 $origin_dtz = new DateTimeZone($origin_tz);
 $remote_dtz = new DateTimeZone($remote_tz);
 $origin_dt = new DateTime('now',$origin_dtz);
 $remote_dt = new DateTime('now',$remote_dtz);
 $offset = $origin_dtz->getOffset($origin_dt) - $remote_dtz->getOffset($remote_dt);
 return $offset;
}