ASP.NET Ajax client-side framework failed to load

Question

I got this error:

ASP.NET Ajax client-side framework failed to load

with the error:

'Sys' is undefined.

The error qppears in IE on the bottom (error message), and appears only when i'm running the site on server. on my localhost everything works fine.

i moved for new server, and there i have the problem. in my previous server everything was fine.

The problem comes from the SCRIPTMANAGER of the ajax.

what i can to do? somthing in the web.config, or should the host company need to install somthing?

ASP.NET 4, IIS 7.5

The ugly yellow triangle on the IE is not what is disturbing me.. the big problem is that the script manager with the update pannel - dont work !

Archy

Yes, nothing works. i lost myself on the searching. maybe here somone will give me the right answer. – Archy

I had these errors, too. Don't recall what the issue was, though. Checking the web.config and that your app pool actually uses .NET 4 would be a good start. – Deify

@UweKeim - thanks. that the first think i did :( . the ugly yellow triangle on the IE is not what is disturbing me.. the big problem is that the script manager with the update pannel - dont work ! :( – Archy

Don't blame the yellow triangle, it's innocent ;-) – Deify

When you use IE's debugging tools, are you able to determine if requests to ScriptResource.axd are coming back with 404 errors? This kind of error is most often caused by problems with the configuration of your site's handler mappings. – Docilla

@lthibodeaux - thanks. i'm trying now this - roelvanlisdonk.nl/?p=1836 – Archy

yep, the tutorial: roelvanlisdonk.nl/?p=1836 fix the problem !! thank you all. – Archy

Answer 1

A quick solution is to update your web.config and add following section

<handlers>
    <remove name="WebServiceHandlerFactory-Integrated"/>
    <remove name="ScriptHandlerFactory"/>
    <remove name="ScriptHandlerFactoryAppServices"/>
    <remove name="ScriptResource"/>
    <add name="ScriptHandlerFactory" verb="*" path="*.asmx" preCondition="integratedMode" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
    <add name="ScriptHandlerFactoryAppServices" verb="*" path="*_AppService.axd" preCondition="integratedMode" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
    <add name="ScriptResource" preCondition="integratedMode" verb="GET,HEAD" path="ScriptResource.axd" type="System.Web.Handlers.ScriptResourceHandler, System.Web.Extensions, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
</handlers>

Evangelistic

That section already exists in my web.config, and the error still occurs. – Ferryboat

Answer 2

I had faced the same issue and the culprit was a web.config file from some other app, that was kept on the web root. (Someone had installed the app on web root) Once it was moved inside a folder, the problem disappeared.

Azerbaijani

Man, I had tried way too many of the solutions above... Yours (the simplest) did the trick. Many thanks for sharing!! – Gifu

Almost 10 years after I need to tell you that out of all pages I've visited and a bunch of similar SO answers/questions, no other answer pointed out what you just did here. In my case, there was a web.config in the root dir as you mentioned (I haven't thought of that possibility until I see this answer). Thank you! – Nitroparaffin

Answer 3

I had the same error and, after a lot of head-scratching, I discovered that the custom HttpModule that I had created was intercepting all Http Requests and wasn't limited to .aspx requests only.

My module evaluated some criteria and redirected to a 404 or 500 page where necessary. The problem was that it was doing this for all requests including the requests for .axd resources such as the ScriptManager.axd. By filtering for .aspx files in the module, it all magically began to work again.

Sometimes it's the things right under your nose that are the problem. I hope that this helps some poor sole and saves them the time and effort it took me.

Cheers,

Kaine

Talaria

How to filtering .aspx files? – Andante

Answer 4

Just for reference purposes, after hunting down this error for two days, we finally found the reason. It was completely different than the other ones stated here.

The effective reason was an erroneous entry in the "Web.config" file. It was this line:

<httpRedirect 
    enabled="true" 
    destination="https://some-domain-of-me.com" 
    exactDestination="false"  
    childOnly="true" />

The whole website worked correctly, except that the ASP.NET Ajax stuff did not load.

Using Firefox and the network log in the web developer console, I saw a huge amount of the same 302 HTTP redirects of some .AXD files. I.e. there was an endless loop which the browser finally killed after approx. 20-30 redirects.

The above line caused these redirects.

My assumption is this behavior:

1. There was an endless redirect for the ASP.NET Ajax .AXD files.
2. The browser tried to load it several times.
3. The browser finally gave up loading of the files.
4. This caused the above error message to be printed:

ASP.NET Ajax client-side framework failed to load

The solution was to remove the (unnecessary) redirect. After this, everything worked fine, again.

(We did the actual redirects we needed then by installing the IIS URL Rewrite module)

Deify

Answer 5

I had the same error for past two days. finally i resolve the issue. add the following items in Managed Handler in IIS.

*.asmx

System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35

ScriptHandlerFactory

*_AppService.axd

System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35

ScriptHandlerFactoryAppServices

ScriptResource.axd

System.Web.Handlers.ScriptResourceHandler, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35

ScriptResource

Zadoc

Hello. I am having a similar problem. I checked these Handler Mappings in IIS 7 and found all the entries. The one difference is that my Version is 4.0. Does anyone know if these are okay with version 4 or if they should use 3.5? – Fogbound

Answer 6

Turns out the solution for me was to remove URL rewrites from the application's site! Most of our site is WordPress static pages, which needed the rewrites; when we converted the application to a site, IIS automatically applied the rewrites.

Mischance