[PHP]json_encode增加options参数后支持中文

----------------------------------------------------------------------------------------------------

header('content-type:text/html;charset=utf-8');
$a = '中文';
echo json_encode($a);//5.3版本以前，无参数情况输出 "\u4e2d\u6587"
echo json_encode($a, JSON_UNESCAPED_UNICODE); // "中文"

Link: http://www.cnblogs.com/farwish/p/3847845.html