Google inside iframe

Hi, trying to use iframe in my project I faced with a problem - some sites are not loading inside iframe, even https://www.google.com/.
https://webix.com/snippet/8fbc3286
Why so?
I would like to make Google authorization using iframe. Is it possible?
Thanks

It seems that google.com cannot be loaded via iframe due to their same origin policy, and it is not a webix-related issue: Edit fiddle - JSFiddle - Code Playground