<script language="javascript">
function check_Only(cb)
{
for (j = 0; j < 7; j++)
{
if (eval("document.myform1.my[" + j + "].checked") == true)
{
document.myform1.my[j].checked = false;
if (j == cb)
{
document.myform1.my[j].checked = true;
}
}
}
}
</script>