To anyone interested I have found the solution for my particular
problem. Using jQuery I used the 'getJSON' method:
$.getJSON('applets/subordinates.php?did=' + nodeId, function(data)
{
var newNode = data.childData;
var ans = {"id" : nodeId, 'children' : newNode};
onComplete.onComplete(nodeId, ans);
});
Additionally, when I returned my data from the PHP page I wrapped it
so that a single element pointed to it (childData):
{ 'childData' : [ {"id" :"54323", "name":"Eric Brown", "data":
{"title":"Assistant,
Executive"}, "children":[]}, {"id" :"7889343", "name":"Susan Clayton",
"data":{"title":"Executive Director"}, "children":[]} ]}
When the data was retrieved I then grabbed the 'childData' and was
able to process it. When the onComplete.onComplete method was called
it successfully added the subtree.