How to insert spreadsheet scripts UI service into google sites?

Question

I create a UI in spreadsheet and need to share/use/embed it in Google site. How do I insert it? Updates: I have tried the following methods to display the apps script UI in Sites 1. added the service URL to gadget that loads iframe. 2. added the service url into a load/get jquery request in a simple html page.

The only way the UI gets visible is when the URL is entered/opened in the browser. Not sure how useful is that?

The service url is obtained when you publish the script as a service and is mostly of the form

https://spreadsheets1.google.com/a/macros//exec?service=AKfycbyAps-kSGjrQY7Wfh7Mtk_a0abCDS36XPQ