Nag screen "Internet Connection is lost". Presenting via browser.

I am presenting via my browser, but when my Internet connection goes off I get a nag screen from Prezi stating that "Internet Connection is lost. You may loose your work".
The worst happened when the nag screen popped during my presentation! :O It ruined my work in front of the officials!
But is there a way to curb future humiliations?

Thank You.