When the code is evaluated from the responseText, it's executed in the limited scope of the loadScript function and because of this, none of these functions will be available outside of the loadScript function. In order do get around this, the for loop adds each function to the window object, thus making it globally available.
It's important to note that only scripts on the same server as the current page can be called in this manner. This is inherent to the XMLHTTP Object and is a necessary measure to increase general browser security.
