//要prototype.jp
function ChangeChikuIndex(srcDropdown, chikuFlg, dstDropdownId) {
    var dstDD = $(dstDropdownId);

    if (srcDropdown.selectedIndex == undefined) {
        ClearOptions(dstDD, true);
    }
    else {
        var selectedValue = $F(srcDropdown);
        var myAjax = new Ajax.Request("ChikuListServer.ashx", { method: 'POST', postBody: 'chikuFlg=' + chikuFlg + '&selectedValue=' + selectedValue, asynchronous: false });
        var respXml = myAjax.transport.responseText;
        ClearOptions(dstDD, false);
        var jo = eval('(' + respXml + ')');
        for (var i = 0; i < jo.itemList.length; i++) {
            dstDD.options[i] = new Option(jo.itemList[i].name, jo.itemList[i].code);
        }
    }

    if (srcDropdown.prototype != undefined && srcDropdown.prototype.clearDropdownList != undefined) {
        for (var i = 0; i < srcDropdown.prototype.clearDropdownList.length; i++) {
            ClearOptions(srcDropdown.prototype.clearDropdownList[i], true);
        }
    }
}

function ClearOptions(dd, addNotSelect) {
    dd.options.length = 0;
    if (addNotSelect == true) {
        dd.options[0] = new Option('指定なし', '');
    }
}