<select style="width:100" onchange="alert(this.value)">
<option value="1111">1111</option>
<option value="2222">2222</option>
<option value="3333">3333</option>
</select>
<option value="1111">1111</option>
<option value="2222">2222</option>
<option value="3333">3333</option>
</select>
function fun(obj)
{
switch(obj.value)
{
case "1":
alert("table 1")
break;
case "2":
alert("table 2")
break;
case "3":
alert("table 3")
}
}
</script>
<select style="width:100" onchange="fun(this)">
<option value="1">table 1</option>
<option value="2">table 2</option>
<option value="3">table 3</option>
</select>