Error “‘Sys’ is undefined” in Asp.Net Ajax
Posted by triaslama on November 29, 2008
When I try ASP.NET Ajax in my development server I get this Javascript error: “‘Sys’ is undefined“. This error occur because I place <asp:ScriptManager runat=”server” /> element in my page.
Wondering why, I search in internet and hope that I will find one of the solution. After several trial and error finally I can find the solution and it work just fine for me.
To solve the error we need to modify web.config file, add the following under <system.web />
<httpHandlers>
<add verb=”GET,HEAD” path=”ScriptResource.axd” type=”System.Web.Handlers.ScriptResourceHandler, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35″ />
</httpHandlers>
Nothing more I can say, but if you get the same error when you work with ASP.NET Ajax try the above solution, and I hope this help.
Read, With the Name of Your Lord Who Created 
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Danny said
Hi,
This solved my problem! Thank You very much for this post 🙂
triaslama said
you’re welcome.
my said
Excellent! I looked at several forumns, which suggested changing lots in the web.config files and which I didn’t want to do. I tried your and VIOLA! it works like a charm. Thank you.
jcentauri said
Indeed useful. Thanks!
Samir said
Thanks…!! it works for me
squatting to pee said
I should email you about it.
shijobaby said
http://sysisundefined.blogspot.com/2009/08/sys-is-undefined-update-panelajax.html
chart said
hoo good
PHP
ASP
AJAX
JavaScript
Bruce Talcott said
Hi,
It works for me. Thanks!!!!
TimWillDoIt said
This hasn’t worked for me yet. I’ve found the same (or similar) solutions all over the Internet. But none of them have helped me. My web.config has all the right lines in all the right places.
This works when I “view in a browser” inside VS2005 but when I copy the files up to the web host server, I get the error, “‘Sys’ is undefined“. It’s a totally blank page with nothing in it but the scriptmanager.
Can someone help me with an explanation why this would work locally but not on the web server. And please don’t tell me that it’s probably the web server because I have no control over that. Thanks.
chandra said
As specified “TimWillDoIt ” , i am facing same problem …can any one help me…many thanks
Regards,
Chandra
bijesh said
thanks man keep u r helping mind
rahul said
Thank you very much.Its really helpful