[SOLVED] PHP cannot write to file

When trying to execute a PHP script that should write text content to a file, I ran into trouble.
First of all, what did I do?

$myfile = '/var/www/dev/log/mylog.log';
$fh = fopen($myfile, 'w');
fwrite($fh, "add some content\n");
fclose($fh);

Then, when executing and nothing happens: I did the following:

• set log directory to writable: 777

But again nothing worked...
Finally I found out that I had to set the owner of the directory.

By typing 'ps aux | grep apache' into the terminal I found out that apache is runned with the user www-data.

Now, when the log folder is owned by www-data user, it becomes accessible for apache. To do this, type: chown www-data /var/www/dev/log/ (or any other folder you want to use). Also make sure the folder is 777 and maybe you need to delete previous logfiles in order to let PHP create new ones.