Reloading Images Using JavaScript
There are some situations where you want to reload an image without refreshing the page containing it. This is especially handy with CAPTCHA images, where you might want to give the user the option to get a new code in case the first is too hard to read.
It sounds simple enough, but then there is browser caching that you need to work around. Fortunately, this problem is easy to solve just by altering the URL of the source, adding a unique string to the end (such as a timestamp) as a GET parameter. Here is a little JavaScript function that will accomplish this:
Bypassing Register_Globals in PHP
Register_globals is an option in PHP that automatically turns special variables (GET, POST, COOKIE, etc.) into global variables. For example, $_GET['id'] becomes $id and this can pose a problem if you already use $id as an internal variable. This option is deprecated and defaults to off in current PHP versions, but may still be enabled on some servers.
If you want to be sure your script works with or without register_globals, here is a snippet the you can add to the beginning of your script:
if(ini_get('register_globals')){ $globals = array_merge($_REQUEST, $_COOKIE, $_SESSION, $_SERVER, $_ENV); $rg = array_keys($globals); foreach($rg as $var){ unset(${$var}); } }
This will unset all variables that match the name in those superglobals, negating register_globals. This should work on PHP version 4.1.0+.
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