Labeling variables

…Once we've gone to the trouble of sanitizing our data, we want to keep…track of that data, and keep track of the fact that we've sanitized it already.…We wouldn't want to sanitize it twice.…And we also want to be able to tell the difference between…data that's safe to use, and…data that's still unsanitized and potentially dangerous.…One way that you can do that is by using variable names as…labels to help us to keep track of the current state of the data.…Words that might be used to describe unsafe…data would be dirty, raw, tainted or unsafe.…And data that's been sanitized could be…referred to as clean, filtered, sanitized or safe.…

I'm sure you can think of others, and you can…come up with your own, custom way of doing this.…The key thing is to give yourself an…identifier so that you can tell the difference.…Let's see an example.…Let's say that we're pulling in an email address from a form.…So that value will reside in the POST super global.…When we bring it into PHP to work with it,…out of POST super global, we're going to assign it to raw_email.…