ASP.NET MVC AJAX Sys is undefined error

Question

I am getting a "Microsoft JScript runtime error: 'Sys' is undefined" error on one of my pages in an MVC application when I attempt an AJAX call. The AJAX call is made from a partial view which is embedded in more than one page. It works fine on all of the pages except one. I have read posts pointing to the web.config file settings and .axd mappings as possible solutions, but the application is configured correctly in the web.config, and the .axd mappings are also correct in IIS. Plus it works fine on all of the pages that use this partial view except one. It is acting like the AJAX libraries are not loading for this one page.

The references to the script files are in the shared site.master file. All of the pages, including the one that doesn't work, reference the same masterpage.

Any ideas? I have been working on this one for two days now. Thanks.

EDIT: As Sam pointed out below, it would seem like the AJAX call is firing before the AJAX libraries have a chance to load. But, the AJAX call is triggered by a submit button long after the page has rendered, so the AJAX libraries have had plenty of time to load - sorry for not giving enough information the first time.

Juan Mellado · Accepted Answer · 2012-04-19 09:51:17Z

20

In web.config add the following line of code under appsettings tag:

<add key="UnobtrusiveJavaScriptEnabled" value="true" />

edited Apr 19, 2012 at 9:51

Juan Mellado

15.2k5 gold badges50 silver badges54 bronze badges

answered Apr 19, 2012 at 9:32

preeti

2012 silver badges2 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

coryrwest Over a year ago

For some reason when installing the nuget package for Microsoft Unobtrusive Ajax this was not added to my Web.Config. Thanks for the tip.

Woworks · Accepted Answer · 2009-12-21 13:48:12Z

17

Just in case... use the following to avoid path issues

<script src="<%= Url.Content("~/Scripts/MicrosoftAjax.debug.js") %>" 
    type="text/javascript"></script>  
<script src="<%= Url.Content("~/Scripts/MicrosoftMvcAjax.debug.js") %>" 
    type="text/javascript"></script>

Source: http://msdn.microsoft.com/en-us/library/dd381533.aspx

Thanks, Arty

answered Dec 21, 2009 at 13:48

Woworks

1,47816 silver badges22 bronze badges

1 Comment

Raj Rao Over a year ago

This seems to be the first thing that people should check - whether they are including the MicrosoftAjax.js and MicrosoftMvcAjax.js files

Sam · Accepted Answer · 2009-06-24 00:34:11Z

4

Load the page in Firefox, then use Firebug to inspect the page - you will be able to see all the individual scripts that have been loaded, plus all the network requests that were issued, and whether they succeeded or not. This is better than trying to troubleshoot from the server perspective.

If you are using IE8, you can use the Developer Tools window, but I think Firebug is better - both tools support JavaScript debugging though.

The most likely problem is that you are running script in your partial view before the scripts it is dependent on have had a chance to load - make sure that any script calls you have inside your partial view will only run once the page has loaded, and not immediately during loading.

answered Jun 24, 2009 at 0:34

Sam

6,29534 silver badges42 bronze badges

2 Comments

cnaegle Over a year ago

@Sam - I Already took a look with firebug and can see both Ajax libraries are loaded when I click on the scripts tab. I am not that familiar with firebug, though, so I might be missing something. I have used fiddler a lot so I will take a look with it tomorrow when I get to the office to verify the call for the scripts are not failing. Since the ajax call is triggered from a submit button long after the page has rendered I would rule out that the scripts haven't had a chance to load. Thanks.

cnaegle Over a year ago

@Sam - took a look with Fiddler this morning and guess what? The path to the scripts file is incorrect for that page only. Don't know why yet, but when I put a fully qualified path in for the scripts, the page works perfectly. Thanks, I am marking your answer as correct since it sent me down the right path - using a tool that would have told me what I needed to know two days ago :)

sunila · Accepted Answer · 2010-10-28 06:36:38Z

3

All the above cases are ok.But sometimes developer forget to add javascript files for ajax .So please check that also.

answered Oct 28, 2010 at 6:36

sunila

311 bronze badge

Comments

drs · Accepted Answer · 2014-08-11 19:24:04Z

1

Basically you might be missing: MicrosoftMvcAjax., MicrosoftMvcValidation.debug and MicrosoftMvcValidation JS file references.

Do the below steps:

PM> Install-Package MicrosoftAjax
PM> Install-Package MicrosoftMvcAjax.Mvc5

Include them in bundleconfig like below:

bundles.Add(new ScriptBundle("~/bundles/mvcFoolProof")
       .Include("~/Scripts/MicrosoftAjax*",
                "~/Scripts/MicrosoftMvcAjax*", 
                "~/Scripts/MicrosoftMvcValidation*",
                "~/Scripts/mvcfoolproof*",
                "~/Scripts/MvcFoolproofJQueryValidation*",
                "~/Scripts/MvcFoolproofValidation*"));

Now it should work without any errors.

edited Aug 11, 2014 at 19:24

drs

5,8754 gold badges49 silver badges68 bronze badges

answered Aug 11, 2014 at 19:00

Manohar Gudivada

212 bronze badges

Comments

Chris Mangiapane · Accepted Answer · 2009-06-24 05:13:23Z

0

Add to web.cofig in section:

 <remove verb="*" path="*.asmx"/>

 <add verb="*" path="*.asmx" validate="false" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>

 <add verb="*" path="*_AppService.axd" validate="false" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>

 <add verb="GET,HEAD" path="ScriptResource.axd" type="System.Web.Handlers.ScriptResourceHandler, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" validate="false"/>

 <add name="ScriptModule" type="System.Web.Handlers.ScriptModule, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>

answered Jun 24, 2009 at 5:13

Chris Mangiapane

1 Comment

cnaegle Over a year ago

As stated above, the web.config file is correctly configured.

GalacticCowboy · Accepted Answer · 2009-12-21 14:02:56Z

0

Regarding your response to Sam, one thing I've noticed in a lot of MVC apps is that people don't know how to deal with the ambiguity of relative paths and the application/runtime. For example, the URL rewriting pretty much guarantees that a particular page can appear at different depths than you anticipated, so ../../images will point somewhere else depending on whether you're looking at /products/widget or /products/widget/12345, even though the view might be the same. As Arty pointed out, the best way to deal with this is to let the engine do the work for you by using a URL utility and application-relative paths that will be fixed up by the application regardless of the context.

answered Dec 21, 2009 at 14:02

GalacticCowboy

11.8k2 gold badges46 silver badges69 bronze badges

Comments

Carl Weis · Accepted Answer · 2010-08-22 10:52:27Z

0

I have also found that using the following works with ASP.NET MVC2.

Instead of using MicrosoftMvcAjax.js, you use MicrosoftMvcValidation.js

Hope this helps someone.

answered Aug 22, 2010 at 10:52

Carl Weis

7,11215 gold badges66 silver badges86 bronze badges

Collectives™ on Stack Overflow

ASP.NET MVC AJAX Sys is undefined error

8 Answers 8

1 Comment

1 Comment

2 Comments

Comments

Comments

1 Comment

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

8 Answers 8

1 Comment

1 Comment

2 Comments

Comments

Comments

1 Comment

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related