PHP5.3以上出现date_default_timezone_set()问题解决方案

date() [function.date]: It is not safe to rely on the system's timezone settings. You are *required* to use the date.timezone setting or the date_default_timezone_set() function. In case you used any of those methods and you are still getting this warning, you most likely misspelled the timezone identifier. We selected 'Asia/Chongqing' for 'CST/8.0/no DST' instead

这是由于调用date时，若timezone设置不正确所产生的E_NOTICE|E_WARNING错误

有以下几种方案可解决该问题：

1. 使用date_default_timezone_set()设置 date_default_timezone_set('PRC');
2. ini_set('date.timezone','Asia/Shanghai');
3. 修改错误级别配置(不推荐)
4. 修改php.ini，显式设置date.timezone=PRC