select的联动

<select name="txtcenter" id="txtcenterid" onchange="checkcenter()">
        <option value="0">请选择</option>
        <%for (int i = 0; i < centerlist.Count; i++)
        { %>
        <option value="<%=centerlist[i].id.ToString() %>"><%=centerlist[i].CenterName.ToString() %></option>
        <%} %>
</select>

<select name="txtdepartment" id="txtdepartmentid" onchange="checkdepart()">
        <option value="0">请选择</option>
</select>

<select name="txtduties" id="txtdutiesid">
       <option value="0">请选择</option>
</select>

 

 

<script type="text/javascript">
            function checkcenter() {
                var centerid = Number(document.getElementById("txtcenterid").value);
                var depart = document.getElementById("txtdepartmentid");
                var duties = document.getElementById("txtdutiesid");
                $("#txtdepartmentid").empty();
                $("#txtdutiesid").empty();
                duties.add(new Option("请选择", "0"));
                depart.add(new Option("请选择", "0"));
                <%for (var j = 1; j < departmentlist.Count; j++)
                  {%>
                if ("<%=departmentlist[j - 1].Centerid%>" == centerid) {
                    depart.add(new Option("<%=departmentlist[j].DepartName%>", "<%=departmentlist[j].id%>"));
                }
                <%}%>
            }
            function checkdepart() {
                var departid = Number(document.getElementById("txtdepartmentid").value);
                var duties = document.getElementById("txtdutiesid");
                $("#txtdutiesid").empty();
                duties.add(new Option("请选择", "0"));
                <%for (var j = 1; j < dutieslist.Count; j++)
                  {%>
                if ("<%=dutieslist[j - 1].Departid%>" == departid) {
                    duties.add(new Option("<%=dutieslist[j].Post%>", "<%=dutieslist[j].id%>"));
                }
                <%}%>
            }
</script>

 

后台：

public static List<CenterGL> centerlist = new List<CenterGL>();
public static List<Department> departmentlist = new List<Department>();
public static List<Duties> dutieslist = new List<Duties>();
protected void Page_Load(object sender, EventArgs e)
{
     centerlist = CenterGLAdapter.Instance.LoadBycompanyid(1);
     departmentlist = DepartmentAdapter.Instance.GetList();
     dutieslist = DutiesAdapter.Instance.GetList();

}