It's confusing, but the Java plugin and the JavaScript interpreter are completely different. The Java plugin comes from Oracle and the JavaScript interpreter is built in to Firefox.

To make sure JavaScript is enabled, use:

Firefox > Preferences > Content >check Enable JavaScript

To see whether you have the Java plugin, and to get it if you don't, try this page:

http://www.java.com/en/download/testjava.jsp

Does that help?

Thank you! Everything else I found told me to go to tools and enable it in the plugins. I have absolutely no idea how it unchecked itself. Again, Thank You!