I just tried updating to the latest AJAX Control Toolkit from a really old version. So far, all the components seem to work except the TabContainer.
I am using VS2010, and ASP.net 4.0 with C#.
The tab does not show, and the page throws a script error upon load:
```
Webpage error details
User Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.1; Win64; x64; Trident/4.0; .NET CLR 2.0.50727; SLCC2; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; InfoPath.3; .NET4.0E)
Timestamp: Fri, 26 Jun 2015 22:52:08 UTC
Message: Expected identifier, string or number
Line: 365
Char: 5
Code: 0
URI: http://localhost:53243/ScriptResource.axd?d=gGy0IYFiFei-bvFLbddGL7lWwVwa6rB96uDiGYwaYBlSXiuqkjwttTmaqs22BD9ZV0eePPVG5MEMrMdKRm3ZPWkB5208jR4DQXqXgXa-K8vbpN0J4J2GPZAfCFGt6Clo0&t=4c030be6
Message: Sys.ArgumentUndefinedException: Value cannot be undefined.
Parameter name: type
Line: 3803
Char: 12
Code: 0
URI: http://localhost:53243/ScriptResource.axd?d=fljd3nXzqvqnwxuNyoHzJXKdgwQAVTCCWbkv8wKW_SpVa765kyr5aHk6Z8XAJ_aSbGTGcorFXPz9m7FcY5CFwUf7O5rj7TZsuTM2R0VYzs72Nhc4wCtt6s1eXjVQVUVqyAP86837dynzdGTeqKrLjsx1tWidUfp6mxbbeiNYD9emxfIpGnPn6ggb6FP6FmLx0&t=7b689585
```
I even verified this by creating a brand new empty Web Application, and dropping a single TabContainer onto the default page. Same deal. Oddly though, the page does view fine in Chrome and Firefox.
```
<%@ Page Title="Home Page" Language="C#" MasterPageFile="~/Site.master" AutoEventWireup="true"
CodeBehind="Default.aspx.cs" Inherits="WebApplication2._Default" %>
<%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="cc1" %>
<asp:Content ID="HeaderContent" runat="server" ContentPlaceHolderID="HeadContent">
</asp:Content>
<asp:Content ID="BodyContent" runat="server" ContentPlaceHolderID="MainContent">
<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.net</a>.
</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 MSDN</a>.
</p>
<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>
<cc1:TabContainer ID="TabContainer1" runat="server" ActiveTabIndex="1">
<cc1:TabPanel runat="server" HeaderText="TabPanel1" ID="TabPanel1">
<ContentTemplate>
test 1
</ContentTemplate>
</cc1:TabPanel>
<cc1:TabPanel ID="TabPanel2" runat="server" HeaderText="TabPanel2">
<ContentTemplate>
test 2
</ContentTemplate>
</cc1:TabPanel>
</cc1:TabContainer>
</asp:Content>
```
I am using the latest Chrome and Firefox versions, but I am using IE8 (because of some stupid legacy tools my company uses break under the newer IE versions).
Comments: I can confirm that this works fine in IE11, so this seems to be an issue just with older versions of IE. I know this is probably a low priority issue, however my company has a lot of users still on older versions of IE, so any help or workarounds that could be provided would be greatly appreciated.
I am using VS2010, and ASP.net 4.0 with C#.
The tab does not show, and the page throws a script error upon load:
```
Webpage error details
User Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.1; Win64; x64; Trident/4.0; .NET CLR 2.0.50727; SLCC2; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; InfoPath.3; .NET4.0E)
Timestamp: Fri, 26 Jun 2015 22:52:08 UTC
Message: Expected identifier, string or number
Line: 365
Char: 5
Code: 0
URI: http://localhost:53243/ScriptResource.axd?d=gGy0IYFiFei-bvFLbddGL7lWwVwa6rB96uDiGYwaYBlSXiuqkjwttTmaqs22BD9ZV0eePPVG5MEMrMdKRm3ZPWkB5208jR4DQXqXgXa-K8vbpN0J4J2GPZAfCFGt6Clo0&t=4c030be6
Message: Sys.ArgumentUndefinedException: Value cannot be undefined.
Parameter name: type
Line: 3803
Char: 12
Code: 0
URI: http://localhost:53243/ScriptResource.axd?d=fljd3nXzqvqnwxuNyoHzJXKdgwQAVTCCWbkv8wKW_SpVa765kyr5aHk6Z8XAJ_aSbGTGcorFXPz9m7FcY5CFwUf7O5rj7TZsuTM2R0VYzs72Nhc4wCtt6s1eXjVQVUVqyAP86837dynzdGTeqKrLjsx1tWidUfp6mxbbeiNYD9emxfIpGnPn6ggb6FP6FmLx0&t=7b689585
```
I even verified this by creating a brand new empty Web Application, and dropping a single TabContainer onto the default page. Same deal. Oddly though, the page does view fine in Chrome and Firefox.
```
<%@ Page Title="Home Page" Language="C#" MasterPageFile="~/Site.master" AutoEventWireup="true"
CodeBehind="Default.aspx.cs" Inherits="WebApplication2._Default" %>
<%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="cc1" %>
<asp:Content ID="HeaderContent" runat="server" ContentPlaceHolderID="HeadContent">
</asp:Content>
<asp:Content ID="BodyContent" runat="server" ContentPlaceHolderID="MainContent">
<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.net</a>.
</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 MSDN</a>.
</p>
<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>
<cc1:TabContainer ID="TabContainer1" runat="server" ActiveTabIndex="1">
<cc1:TabPanel runat="server" HeaderText="TabPanel1" ID="TabPanel1">
<ContentTemplate>
test 1
</ContentTemplate>
</cc1:TabPanel>
<cc1:TabPanel ID="TabPanel2" runat="server" HeaderText="TabPanel2">
<ContentTemplate>
test 2
</ContentTemplate>
</cc1:TabPanel>
</cc1:TabContainer>
</asp:Content>
```
I am using the latest Chrome and Firefox versions, but I am using IE8 (because of some stupid legacy tools my company uses break under the newer IE versions).
Comments: I can confirm that this works fine in IE11, so this seems to be an issue just with older versions of IE. I know this is probably a low priority issue, however my company has a lot of users still on older versions of IE, so any help or workarounds that could be provided would be greatly appreciated.