The syntax in your "showHide" function makes no sense. You cannot compare properties using the assignment (=) operator. And there is no validity in assigning the value of one property to an unrelated one in an if statement. A more reasonable approach would be:

function showHide (chkID, divID)
{
 var x=document.getElementById(divID);
 if (document.getElementById(chkID).checked)
    x.style.display='block';
 else
    x.style.display='none';
}