penders - 9:08 pm on Sep 21, 2013 (gmt 0)
Look at what it says and decide whether you need to do something about it.
PHP Warnings are just that, they are warning you of something that might be a potential error. But the compiler is unable to determine whether it is serious or not - that is for you to decide. A "Warning" could be the result of a serious error in your code, or it might be by design (or at least expected).
"this variable hasn't been declared before using it"
Failure to initialise a variable could be because your initialisation code hasn't executed correctly, or at all. Or, if your code follows a different path then the variable does get initialised... to something you weren't expecting? But only you will know for sure (and that is also a problem).
If you are working with other developers, or you are sharing your code then you really need to resolve these warnings. And as mentioned above, by eliminating these warnings, it will make development/debugging a lot easier.
I used to like bunching stuff into one line like
implode(',',array_reverse(explode('.',$_SERVER['REMOTE_ADDR']))); ... but apparently newer versions of PHP don't like that.
Not sure why newer versions of PHP don't like that? (It works OK for me.)