php mb_convert_encoding文字编码转换函数

$str='脚本学堂:http://bbs.it-home.org';
echo mb_convert_encoding($str, "utf-8"); //编码转换为utf-8
$str='程序员之家:http://bbs.it-home.org';
echo mb_convert_encoding($str, "utf-8", "gbk"); //已知原编码为gbk，转换为utf-8
$str='程序员之家:http://bbs.it-home.org';
echo mb_convert_encoding($str, "utf-8", "auto"); //未知原编码，通过auto自动检测后，转换编码为utf-8
?>