ModalPopup - The 'Unable to set property 'actControlType' of undefined or null reference' error occurs in IE10

Hello,

I have a WebForm app. using .NET 4.5 and AjaxControlToolkit 16.1 and in IE10 I get a first NotFound javascript error in ModalPopup.js at line 131:

this._foregroundElement.parentNode.removeChild(this._backgroundElement);

and then an "Unable to set property ‘actControlType’ of undefined or null reference’ at line 180:

this._backgroundElement.dataset.actControlType = "modalPopupBackground";

It works fine in IE Edge, Chrome and Firefox. Not sure if it counts but the ModalPopupExtender that fails is declared in a TabPanel (complete hierarchy is asp:Content > ajaxToolkit:TabContainer > ajaxToolkit:TabPanel > ContentTemplate > ajaxToolkit:ModalPopupExtender)

[Tagmar2]

html5-dataset.js works!

My solution:

If Request.Browser.Browser = "IE" Then
            Dim V as string = Request.Browser.Version

            If V= "10.0" OrElse V= "9.0" Then
                ToolkitScriptManager1.Scripts.Add(New ScriptReference("~/Scripts/html5-dataset.js"))
            End If
  End If

[AlekseyMartynov]

@motleydrew

I’m seeing this as closed, but I do not see the resolution.

We use the “Closing issues via commit messages” practice. The “Closed” state means that a fix has been merged into the master branch and will be available in the next release of Toolkit. Before that, it’s possible to clone or download the Git repository and compile a custom build from source code.