Microsoft JScript runtime error: 'document.getElementById(...)' is null or not an object

Ajay Gautam

16y17.4k.NET

Hi,
I have one text box and that textbox should contain firstname.lastname.
I am doing Client side validation.

I am getting error Microsoft JScript runtime error: 'document.getElementById(...)' is null or not an object.

ASPX code :-

function validateTextBox(str)
{
alert(str);// Getting proper value
if (str.indexOf(".") == -1)
{
alert("Username should have period(.) between firstName and LastName like FirstName.LastName or FirstNameMI.LastName");
document.getElementById('ctl00_ContentPlaceHolder1_txtUsernameB').focus();
// Here i am getting error...

return false;
}
}

Username

Username is required.

Username already exists. Please specify a different username.

CS Code

----------

protected void BtnNewAccountByRequestorNext_Click(object sender, EventArgs e)
{
if (RbAccount.SelectedValue.Equals("new"))
{
Page.RegisterStartupScript("anykey", "");
}

}

Any help appreciated...

6 Replies

Know the answer? Post it — somebody with the same question will find it here.

Suthish Nair16y ago

Accepted answer

Hi,
If the validation needs to happen on button click.

Try this, better way instead if using RegisterStartupScript.

    protected void Page_Load(object sender, EventArgs e)
    {
        String s = String.Format("javascript:validateTextBox('{0}', '{1}', '{2}');", TextBox1.Text, TextBox1.ClientID, RadioButtonList1.SelectedItem.Text);
        Button1.Attributes.Add("onclick", s);
    }

Ajay Gautam16y ago
Its done, i handled this through server side
0
Ajay Gautam16y ago
Hi Murali,
Like this it is working fine, but i need to specify one condition like if my New radiobutton is selected then this should validate otherwise no..

if (RbAccount.SelectedValue.Equals("new"))
        {
            // code
        }
0
16y ago

I tried this and this is working. Can you check your js code once.
<%@ 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">
asp:Content>
<asp:Content ID="BodyContent" runat="server" ContentPlaceHolderID="MainContent">
<script type="text/javascript">
function Validate() {

var txtCtrl = '<%= TextBox1.ClientID %>';
//alert(txtCtrl);
document.getElementById(txtCtrl).focus();
return false;
//document.getElementById(txtCtrl).value = "Murali";
}
script>
<h2>
Welcome to ASP.NET!
h2>
<p>
To learn more about ASP.NET visit <a href="http://www.asp.net" title="ASP.NET Website">www.asp.neta>.
<asp:TextBox ID="TextBox1" runat="server">asp:TextBox>
<asp:Button ID="Button1" runat="server" Text="Button" OnClientClick="Validate();" />
p>
<p>
You can also find <a href="http://go.microsoft.com/fwlink/?LinkID=152368&clcid=0x409"
title="MSDN ASP.NET Docs">documentation on ASP.NET at MSDNa>.
p>
asp:Content>
0
Ajay Gautam16y ago
Hi Murali,
Thanks for your reply.

I tried both methods, Still its showing same error
0
16y ago
Are you hardcoded the id here? [ document.getElementById('ctl00_ContentPlaceHolder1_txtUsernameB').focus()].
Method 1:
var txtUsernameID = '<%= txtUsernameB.ClientID %>';

document.getElementById(txtUsernameID).focus();

Method 2:
Try passing the ClientID from the server side ...
function validateTextBox(str,id)
{
//your existing code here.
document.getElementById(id).focus();
}

In the server, call like this,
Page.RegisterStartupScript("anykey", "");
0