Modal Dialog in Autohosted Sp2013 App

I am stuck with a problem and thought that maybe one of you can help me with it.

I have a autohosted Sharepoint App. The app consists of several aspx pages. What I want to do is that one of the pages is the Main page and there are buttons for the other pages. If the user clicks on one of them, the according aspx opens in a modal dialog. So the users nevery really leaves the Main page.

I tried it using this script:

 $.getScript(scriptbase + 'SP.Runtime.js', function () { $.getScript(scriptbase + 'SP.js', function () { $.getScript(scriptbase + 'SP.RequestExecutor.js', Showdialog); } ); } ); function Showdialog() { var options = { url: "/_layouts/15/InDialog.aspx", tite: 'Sharing Information', allowMaximize: false, showClose: true, width: 430, height: 230 }; SP.SOD.execute('sp.ui.dialog.js', 'SP.UI.ModalDialog.showModalDialog', options); return false; 

But all i get is a SOD is undefined exception when i execute this code.

What am I missing?

thanks in advance

best regards

Alex