Dear Friend, thanks for reply.
But I have already readed those documents, and it just said the password using the MD5 algorithm. But as I said above, the result of MD5() is not equal with the string stored in .htpasswd. I found the string stored in .htpasswd is not exclusive. It would change each time added. So, how can I use a php function to encrypt a password that visitor inputed to compare it? Could you give me some advice?
Thanks.