I just tried many examples of google scripts found at: https://developers.google.com/apps-script/guides/html/
But I always get the error
"Error parsing the sandbox attribute:" enable modalities "," allow pop-ups "-" run "- these are invalid sandbox flags.
I tried with Chrome and Safari on Mac OS and Chrome on Win 8.
This error can be safely ignored, the script will continue to work fine. These are two new flags that were implemented in Chrome 46 (current stable release). If you are testing in a browser that does not support them, you will see this error (this is really just a warning).
The allow-modals is required because Chrome by default blocks modal dialogs in an isolated iframe . Adding this flag allows modules to work in your application scripts.
allow-modals
The allow-popups-to-escape-sandbox flag is somewhat similar; its purpose is to allow the creation of new windows without restricting them to the same sandbox restrictions .
allow-popups-to-escape-sandbox