When Pressing "back" In A Web Browser, Radio Button Selection Is Still Retained

I have a page where you select a radio button and submit to get certain results. When pressing the back button to get back to the original search page, however, the radio button is still selected, but the page lists it's value as undefined. I wish to do one of the following:

1) assign the radio button's value to what it is actually showing

2) clear out all selections

Here is some relevant code:

Code:
function PageLoad()
{
document.all.item("radioSearch").value = 0;
alert(document.all.item("radioSearch").value)

[Code].....