switch

HTML

<select id="brandSelect" onchange="brandSelect()">
        <option value="10">Pilih Brand</option>
        <option value="20">AMD</option>
        <option value="30">Intel</option>
</select>

<select id="socketSelect">
        <option>Pilih Socket</option>
</select>


<script type="text/javascript">
function brandSelect(){
    var x = document.getElementById("brandSelect");
    var selectedValue = parseInt(x.options[x.selectedIndex].value);

    switch(selectedValue) {
        case 10:
            break;
        case 20:
            var y = document.getElementById("socketSelect");
            var am4 = document.createElement("option");
            var am3 = document.createElement("option");
            var am2 = document.createElement("option");
            am4.text = "AM4";
            am3.text = "AM3";
            am2.text = "AM2";
            y.add(am4);
            y.add(am3);
            y.add(am2);
            break;
        case 30:
            break;
    }
}
</script>