Show and Hide Text in asp.net

About.aspx=>
<%@ Page Title="About Us" Language="C#" MasterPageFile="~/Site.master" AutoEventWireup="true"
    CodeFile="About.aspx.cs" Inherits="About" %>
<asp:Content ID="HeaderContent" runat="server" ContentPlaceHolderID="HeadContent">
<script type="text/javascript">
    function display(id) {
        var traget = document.getElementById(id);
        if (traget.style.display == "none") {
            traget.style.display = "";
        } else {
            traget.style.display = "none";
        }
    }
    </script>
    <style type="text/css">
        #menu
        {
            height: 12px;
        }
    </style>
</asp:Content>
<asp:Content ID="BodyContent" runat="server" ContentPlaceHolderID="MainContent">
    <div>
        <input type="button" onclick="display( 'menu' )" value=" Show / Hidden " />

        <div id="menu">DHTML using DISPLAY</div>
    </div>
</asp:Content>