操作方法
$str = '<p><span style=";font-family:微软雅黑;font-size:16px"> <span style="font-family:微软雅黑">'; htmlspecialchars_decode($str)
返回 '<p><span style=";font-family:微软雅黑;font-size:16px"> <span style="font-family:微软雅黑">'