I asked this question and now that I have the book I am trying to implement the code.
This was the accepted answer from Dave Baldwin.
I'm trying to call a php file that will echo html. I may need this spelled out a little more for me.
var myDiv = document.getElementById("myDiv");
document.getElementById("mySelect").onchange = someFunction(this);
data: 'content=' + object.value,
// A response to say if it's updated or not