How to prompt user to answer a question (yes or no)?

[Manuel Reimer]

Hello,

currently I'm using "window.confirm". This works "OK" but doesn't look 
that nice and I would like to have a checkbox in the message box to 
allow the user to choose that his choice should be remembered.

Is there a nice, simple way to do this?

I need my code to block as long as it takes for the user to make a 
choice, so *please* no asynchronous stuff like promises.

Manuel