I have a set of CHECKBOXES where if I check one of those checkboxes then one of a set of RADIO BUTTONS needs to be selected in the same form in addition to populating a textbox with the contents of a variable in my form that corresponds to the checkbox being checked. I am having problems trying to get this done. I've tried the following but to no avail.

Any suggestions or direction would be appreciated.

Here is the code for one of my checkboxes:
<tr>
    <td align="left" nowrap><input type="checkbox" name="chkplatinum" value="platinum" onclick="this.form.sponsor_info[0].selected=1">
&nbsp;&nbsp;PLATINUM LEVEL $25,000+</td>
</tr>

And here is the code for one of my radio buttons and the textbox:
<input Type="Radio" Name="sponsor_info">
&nbsp;&nbsp;&nbsp;Sponsorship Level <b>$</b> <input type="text" name="level_amt" size="10">&nbsp;(min. amt denoted per level checked at right)<br><br>

In response to my own question, I was trying to create a function that encapsulates both events that I am trying to do but when I call this function I am getting an error.

Here is the function:

function chkPlatinumValue()
{
    var chkplatinumamount = "25000.00";
    if (theForm.chkplatinum.checked = true)
    {
        theForm.sponsor_info.checked = true;
        theForm.level_amt.value = chkplatinumamount;
    }
}

Here is where I am calling this function:
<td align="left" nowrap><input type="checkbox" name="chkplatinum" onclick="return chkPlatinumValue();">

Here is the error:
object expected


ANY help would be appreciated. Thanks.