If you are going to go with XML, you could just stick with an XML object and traverse that for your data much like you would a multidimensional array. If it's easier to understand by parsing your XML into and array then go for it. Plus if the php can just pass back an xml formated string, you can skip dealing with a text document altogether and just use XML.load('somephp.php')

But yeah it sounds like you understand. The for loop generates the iterant value which is then used for look up during assignment.

For real time updates you want to look into opening a socket connection.

Your biggest problem is trying to get this all working at once. The number one rule of programming is "Never add functionality early."

Fall back a little and just worry about getting the UI generated. Then worry about making them clickable, then worry about what happens on click. One thing at a time.