Couple Qs - Radio Buttons and Interval Code

[dcloud]

I added two radio buttons to my form, both initial state unchecked. When a visitor selects one of the radio buttons, he can not undo it by clicking again. Is there a code I can use to fix this...?

Also, does someone know a code I could use to open an html file, leave it open for about 5 seconds, and load the main file? Like they do in ads, before entering the page.

Thank you.

- dc