chatBox.js

//stateChangeHandler will fire when the state has changed, i.e. data is received back 
// This is non-blocking (asynchronous) 
function stateChangeHandler() {
    //readyState of 4 or 'complete' represents that data has been returned 
    if (xmlHttp.readyState == 4 || xmlHttp.readyState == 'complete') {
        //Gather the results from the callback 
        var str = xmlHttp.responseText;
        if (str != "") {            
            //document.getElementById('msgPanel').innerHTML += str;            
            var msgs = str.split('#');

            for (ind = 0; ind < msgs.length; ind++) {
                msgs[ind] = msgs[ind].replace("_@HASH__", "#");
                var msg = msgs[ind].split("&");
                msg[0] = msg[0].replace("_@AMP__", "&");
                msg[1] = msg[1].replace("_@AMP__", "&");
                msg[2] = msg[2].replace("_@AMP__", "&");

                document.getElementById('msgPanel').innerHTML += "<br><b>" + msg[0] + ": </b>" + msg[2];
                // Change here
                var msgPanel = document.getElementById("msgPanel");
                msgPanel.scrollTop = msgPanel.scrollHeight;
            }
        }
    }
}