Issue with Modal Dialog in SharePoint 2013

Question

Foll. is our code to open modal dialog in SharePoint 2013. It worked in 2010. In 2013, I have put a debugger and notice that the debugger wont go into the line after ExecuteOrDelayUntilScriptLoaded. What might be the issue?

function OpenDialog(url, width, height) {
    debugger;
    ExecuteOrDelayUntilScriptLoaded(openModalDialog, "SP.JS");
    function openModalDialog() {
        options = SP.UI.$create_DialogOptions();
        options.url = url;
        options.showClose = false;
        options.allowMaximize = false;
        if (width != '') {
            options.width = width;
        }
        if (height != '') {
            options.height = height;
        }

        options.dialogReturnValueCallback = Function.createDelegate(null, CloseCallback);
        SP.UI.ModalDialog.showModalDialog(options);

    }
}

function CloseCallback(result, target) {

}  

*UPDATE: I changed the code to the foll. and it has resolved the issue. I would like to know whats happening in SP2013 that is causing this issue?*

 function OpenDialog(url, width, height) {
            debugger;
            var options = {
                url: url,
                showClose:false,
                allowMaximize:false
            };

            if (width != '') {
                options.width = width;
            }
            if (height != '') {
                options.height = height;
            }

                options.dialogReturnValueCallback = Function.createDelegate(null, CloseCallback);
                SP.SOD.execute('sp.ui.dialog.js', 'SP.UI.ModalDialog.showModalDialog', options);

            }


        function CloseCallback(result, target) {

        }  

Answer 1

In SP2013 this is the correct way to do it according to Microsoft @ http://msdn.microsoft.com/en-us/library/jj245759.aspx

// Make sure the SharePoint script file 'sp.js' is loaded before your // code runs.

SP.SOD.executeFunc('sp.js', 'SP.ClientContext', openModalDialog);

Reference:

ExecuteOrDelayUntilScriptLoaded not executing after page publish