I have a script like this :

script type="text/javascript" language="javascript">
function ToggleVisibility(cbo1, lbl1)
{
alert("sid" + lbl1);

lbl1.style.visibility='hidden';

cbo1.style.visibility='visible';


}

</script>


But, it give me an error style.visibility is null or not an object. cbo1 and lbl1 has the right values. Pls help.