IE 10 Throws "0x800a1391 - JavaScript runtime error: 'jQuery' is undefined" (ASP.NET)

Question

I have searched through probably 15 different answers here and other sites.

Whenever I run my ASP.NET application in IE 10, I get the following error before it finishes loading:

I am NOT running in Compatibility mode (I checked). I even have it disabled on the Site Master because Compat mode breaks the layout. Further, I am not actively using jQuery anywhere in my application that I am aware of.

The application runs fine when testing in Chrome and FireFox.

It also works just fine in IE on our production server currently. My local copy is the exact same as the production copy and I still get the error. My theory is that it's an IE setting, but I can't figure out what.

When the problem started, I was literally just editing a background color on an .aspx page; something I had changed and successfully ran seconds earlier. So I highly doubt it's related to my code.

Failed Troubleshooting Solutions:

• Reverting to a previous version of my application using SVN.
• Checking out a fresh copy of the production version of my app (working in production with IE 10 without issue).
• Using NuGet to update everything.
• Repairing Visual Studio.
• Using Update-Package in the Package Manager.
• Using IE's developer tool to see if any errors are thrown on the production server (none), as I can't use it on my local copy since it won't load.
• Unchecking "Display intranet sites in Compatibility View".

Thank you for any insight!

Answer 1

Daniel Corzo's comment pointed me in the right direction. Way simpler than I thought.

All I had to do was add

<script src="http://code.jquery.com/jquery-1.9.1.js"></script>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js"></script>

<script src="http://netdna.bootstrapcdn.com/bootstrap/3.0.0/js/bootstrap.min.js"></script>
<script src="http://code.jquery.com/ui/1.10.3/jquery-ui.js"></script>

inbetween my head tags on my Site.Master ASPX page. I put it immediately after my code that forces the site to run in Compatibility mode (since that has to be first or it won't work).

I'm still not sure what triggered it to start throwing an error in the first place.

I overlooked this simple solution because it had been working for almost an entire year before throwing this error.

Either way, thanks for pointing me in the right place Daniel!