php decode hacked my site
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
so i knew that my site has been hacked..
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['name'])
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???
thanks in advance and have a nice day