how to unvisiable lable when value select in dd in asp.net

Question

Hi frnds

i have a asp form where dropdownlist.from to this dropdown i selected value so here i want if i select on perticular department so some textbox n labee

should be hide .i am able to do text box but how to unvisible label

my code like this

<div class="row form-group">

<label class="col-md-2 col-xs-12" for="<%=ddlDepartName.ClientID %>">

Department Name<span class="redtext">* </span>:</label>

<div class="col-md-6 col-xs-12">

<asp:DropDownList ID="ddlDepartName" CssClass="form-control" runat="server" AutoPostBack="True"

CausesValidation="false">

</asp:DropDownList>

</div>

</div

dropdown i can hide but if i hide this label is visiable

please clera this.its urgebt