jQuery $.cookie is not a function

Here are all the possible problems/solutions I have come across:

1. Download the cookie plugin

$.cookie is not a standard jQuery function and the plugin needs to be downloaded here. Make sure to include the appropriate <script> tag where necessary (see next).

2. Include jQuery before the cookie plugin

When including the cookie script, make sure to include jQuery FIRST, then the cookie plugin.

<script src="~/Scripts/jquery-2.0.3.js" type="text/javascript"></script>
<script src="~/Scripts/jquery_cookie.js" type="text/javascript"></script>

3. Don’t include jQuery more than once

This was my problem. Make sure you aren’t including jQuery more than once. If you are, it is possible that:

1. jQuery loads correctly.
2. The cookie plugin loads correctly.
3. Your second inclusion of jQuery overwrites the first and destroys the cookie plugin.

For anyone using ASP.Net MVC projects, be careful with the default javascript bundle inclusions. My second inclusion of jQuery was within one of my global layout pages under the line @Scripts.Render("~/bundles/jquery").

4. Rename the plugin file to not include “.cookie”

In some rare cases, renaming the file to something that does NOT include “.cookie” has fixed this error, apparently due to web server issues. By default, the downloaded script is titled “jquery.cookie.js” but try renaming it to something like “jquery_cookie.js” as shown above. More details on this problem are here.