มี List / Menu หลายอัน ถ้าเลือกอันนึงอันใด ที่เหลือจะ Disable

<script language="JavaScript">
		function fncDisabled1()
		{
			document.getElementById('1').disabled = false;
			document.getElementById('2').disabled = true;
			document.getElementById('3').disabled = true;
			document.getElementById('4').disabled = true;
		}

		function fncDisabled2()
		{
			document.getElementById('1').disabled = true;
			document.getElementById('2').disabled = false;
			document.getElementById('3').disabled = true;
			document.getElementById('4').disabled = true;
		}
		function fncDisabled3()
		{
			document.getElementById('1').disabled = true;
			document.getElementById('2').disabled = true;
			document.getElementById('3').disabled = false;
			document.getElementById('4').disabled = true;
		}
		function fncDisabled4()
		{
			document.getElementById('1').disabled = true;
			document.getElementById('2').disabled = true;
			document.getElementById('3').disabled = true;
			document.getElementById('4').disabled = false;
		}
</script>

<select name="1" id="1"onClick="JavaScript:fncDisabled1();">
<select name="1" id="2"onClick="JavaScript:fncDisabled2();">
<select name="1" id="3"onClick="JavaScript:fncDisabled3();">
<select name="1" id="4"onClick="JavaScript:fncDisabled4();">