$str="中文";
echo json_encode($str);显示为：
[null] 所以打算用htmlentities 转一下：
$str=htmlentities($str,utf-8);
echo json_encode($str);结果出现一个很郁闷的问题
Notice: Use of undefined constant utf - assumed 'utf' in F:\工作\test.php on line 24["\ufffd\ufffd\ufffd\u052a\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\uccef\ufffd\ufffd\ufffd\ufffd\u3d22\ufffd\ufffd "]
line 24：$str=htmlentities($str,utf-8);看结果转换成功了 ，但是不知道为什么 报错了！
echo json_encode($str);显示为：
[null] 所以打算用htmlentities 转一下：
$str=htmlentities($str,utf-8);
echo json_encode($str);结果出现一个很郁闷的问题
Notice: Use of undefined constant utf - assumed 'utf' in F:\工作\test.php on line 24["\ufffd\ufffd\ufffd\u052a\ufffd\ufffd\ufffd\ufffd\ufffd\ufffd\uccef\ufffd\ufffd\ufffd\ufffd\u3d22\ufffd\ufffd "]
line 24：$str=htmlentities($str,utf-8);看结果转换成功了 ，但是不知道为什么 报错了！
即报错 又是[null] $_title=htmlentities($_title,"utf-8");iconv我试试看