alert shows undefined in javascript when passed value form aspx.cs page

Question

 string locationName = "Mumbai";
    Page.ClientScript.RegisterStartupScript(Type.GetType
    ("System.String"), "addScript", "PassValues(" + locationName + ")", true);

in javascript my code contains

<script language="javascript" type="text/javascript">
        function PassValues(locationName)
            {
             var txtValue = locationName; 
             alert(txtValue);
            }
</script>

Here the alert shows undefined instead of "Mumbai"

Answer 1

Try putting single quotes around your variable in the code behind. Without them, the browser thinks you are passing in a variable named Mumbai. What you really want to pass is the string 'Mumbai'. You get the message, 'undefined', because there is no variable named Mumbai in the client side code.

 string locationName = "Mumbai";
    Page.ClientScript.RegisterStartupScript(Type.GetType
    ("System.String"), "addScript", "PassValues('" + locationName + "')", true);

Answer 2

this works perfectly for me:

Default.aspx.cs

using System;
using System.Web.UI;

namespace WebApplication2
{
    public partial class _Default : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            string locationName = "Mumbai";

            Page.ClientScript.RegisterStartupScript(Type.GetType("System.String"), "addScript", "PassValues('" + locationName + "')", true);
        }
    }
}

Default.aspx ( auto generated as content page from Visual Studio 2010 when created the new web application for testing )

<%@ Page Title="Home Page" Language="C#" MasterPageFile="~/Site.master" AutoEventWireup="true"
    CodeBehind="Default.aspx.cs" Inherits="WebApplication2._Default" %>

<asp:Content ID="HeaderContent" runat="server" ContentPlaceHolderID="HeadContent">

<script language="javascript" type="text/javascript">
    function PassValues(locationName) {
        var txtValue = locationName;
        alert(txtValue);
    }
</script>

</asp:Content>
<asp:Content ID="BodyContent" runat="server" ContentPlaceHolderID="MainContent">
    <h2>
        Welcome to ASP.NET!
    </h2>
</asp:Content>