I use onClick event in a radio button to open a new window in the form.

<input type="radio" name="S1" value="ABC" tabindex="28" onClick="window.open('test.html', 'new', 'width=200,height=220')" id="radio4">

Itís open the window and works fine. When I go to the next page, then click (go) back, the form is clear out. Does anyone know why? How to keep the form ? Thanks for your help.