PHP provides only a basic implementation of type hinting, namely for arrays and objects. Currently there's no way to determine if a given variable is a string, a boolean, an object or anything else. Thus, many PHP developers prepend a prefix to each variable name in order to determine if a given variable contains a certain type. The following table summarizes some possible prefixes:
$strUA = $_SERVER['HTTP_USER_AGENT']; $arBrowserInfo = get_browser(null, true);
In my opinion, this is a useful way to improve the overall readability of our code. By doing so, we'll stop asking to ourselves whether a given variable contains a certain type or not.