You should be aware that using mode 777 means that anybody on the system can read and write that file or directory. If you're on a shared system, anybody else on the system can edit or delete files in a mode 777 directory. Even if you have a system to yourself, giving permissions to everybody to write someplace can make a minor security problem (like disk access as user nobody) into a big one.

If you really don't care about the files or directories with mode 777 being changed by random users, those permissions are fine. Sometimes that's true, as in /tmp. Mostly, though, it's not true, and you should find a more restrictive set of permissions that allows your script to write to that directory, without allowing the rest of the world as well.