mystem2.js

Mysystem2.prototype.render = function() {
    var latestState = this.getLatestState();
    if (latestState !== null) {
        /*
     * get the response from the latest state. the response variable is
     * just provided as an example. you may use whatever variables you
     * would like from the state object (look at templatestate.js)
     */
        var latestResponse = latestState.response;
        this.domIO.textContent = latestResponse;
    }

    // It turns out that sometimes when firebug is enabled and reloading
    // the page and switching back to the step: The SC.onReady.done method is never called
    // which should mean the jquery ready method is never called either.  
    // It seems this has to do with how the step iframe is setup. Its contents are injected
    // instead of loading it from a url.  So far the approach below seems to fix this problem
    // and not cause other problems.
    if (!SC.isReady) {
        SC.onReady.done();
    }
    
    var lastRenewal = 0;
    if (typeof eventManager != 'undefined') {
        // watch for changes to the student data and renew the session whenever it changes
        $('#my_system_state').bind("DOMSubtreeModified", function() {
            var now = new Date().getTime();
            if (now - lastRenewal > 15000) { // only renew at most once every 15 seconds
                SC.Logger.log("renewing session");
                eventManager.fire('renewSession');
                lastRenewal = now;
            }
        });
    }
    
    if (this.content) {
        MySystem.loadWiseConfig(this.content, latestState);
    }
    if (latestState) {
        MySystem.updateFromDOM();
    }
};

/**
 * This function retrieves the latest student work

line 30 is triggering a renewsession event, because the 'student' data in #my_system_state is being modified.
Its actually not being modified. We could do a simple compare on the text value before triggering the event.

I am seeing about 15 or so events being triggered at once here, each with their own var context.

So my guess is that "render" is being called fresh for every "renewSession". -- in which case we don't want to call 'renewSession here' , but instead some data saving method.