Sharepoint 2010 Add item with Javascript failing with undefine error and apply error

Question

I am attempting to use the below code to add an item to my list. It is almost a direct copy from the MSDN website with the only changes being variable names.

If use this.oListItem = oList.addItem(itemCreateInfo); I get 'oListItem' is undefined error and nothing is added to the list.

If I change the above line to var oListItem = oList.addItem(itemCreateInfo); the it throws an error code SCRIPT5007: Unable to get property 'apply' of undefined or null reference but the list item is is added. However the onAddClassSucceeded is not trigger.

I know this has been asked in other post but I could not find acceptable answers for either situation. Changing this to var was one answer but it cause other issues.

Note: sp.js is loaded via the _spBodyOnLoadFunctionNames.push('_init');

How do rectify either of these issues?

    function createClassItem() {
        // Create a list item in the Classes list

    var ctx = new SP.ClientContext.get_current();
    var oList = ctx.get_web().get_lists().getByTitle('Classes');

    var itemCreateInfo = new SP.ListItemCreationInformation();
    var oListItem = oList.addItem(itemCreateInfo);
    //    debugger;
    oListItem.set_item('Title', '0');
    oListItem.set_item('reportDate', document.getElementById('reportDate').value);      
    oListItem.set_item('startDate', document.getElementById('startDate').value);
    oListItem.set_item('endDate', document.getElementById('endDate').value);


    oListItem.update();

    ctx.load(oListItem);

    ctx.executeQueryAsync(
        Function.createDelegate(this, this.onAddClassSucceeded),
        Function.createDelegate(this, this.onAddClassFailed));
}

function onAddClassSucceeded(sender, arg) {

    SP.UI.Notify.addNotification('Item created');
}

function onAddClassFailed(sender, args) {

    SP.UI.Notify.addNotification('Request failed. ' + args.get_message() + '\n' + args.get_stackTrace());
}

Answer 1

Please try calling createClassItem after sp.js gets loaded like this

ExecuteOrDelayUntilScriptLoaded(createClassItem, 'sp.js');

Also add console logs in success and fail handlers to see what error its throwing if any.