RadioButtonList and JavaScript

In my ASP.Net page, I have implemented a RadioButtonList server control with id="txtCreditType". The HTML that is rendered by the control is as follows:

<table id="txtCreditType" cellspacing="0" cellpadding="0" border="0" style="border-collapse:collapse;">
<tr>
<td>
<input id="txtCreditType_0" type="radio" name="txtCreditType" value="Individual" />
<label for="txtCreditType_0">Individual</label>
</td>
<td>
<input id="txtCreditType_1" type="radio" name="txtCreditType" value="Joint" /><label for="txtCreditType_1">Joint</label>
</td>
</tr>
</table>

I would like to uncheck both of the radio buttons on the client-side (leaving nothing checked). I will then disable the control. This is part of a client-side clean-up procedure. I do not have a problem disabling the control in javascript (that seems to work great). However, I cannot uncheck either of the radio buttons. I think it may be a syntax issue.

Could someone please provide the appropriate method for unchecking both of the radio buttons?

Thank you in advance.

To uncheck the radio buttons, you can use the following function:

function uncheckRButtons() {

for (i=0; i<document.formname.radioname.length; i++) {

document.formname.radioname[i].checked=false;

}

}