直接上代码，不废话

 $('select[name="sealType"]').change(function (event) {
        let value = event.target.value
        queeryDeptListBySealType(value)
    })


    // 获取科目信息
    function queeryDeptListBySealType(value){
        $.ajax({
            type: "post",
            url: prefix + "/queeryDeptListBySealType",
            data: {"sealType": value},
            success: function(result) {
                if (result.code == 0) {
                    removeAll();
                    // result.data 是数据集合
                    let deptList=result.data;
                    var select = document.getElementById("sealCompany");
                    var option = document.createElement("option");
                    option.value = "";
                    option.text = "--请选择--";
                    select.appendChild(option);
                    $.each(deptList, function(i,item){
                        var option = document.createElement("option");
                        option.value = item.deptId;
                        option.text = item.deptName;
                        select.appendChild(option);

                    });
                }else {
                    return $.modal.alertWarning(result.msg);
                }

            }
        });
    }

    function removeAll(){
        let sealCompany=document.getElementById('sealCompany');
        sealCompany.options.length=0;
    }

对应后端业务接口如下：