Javascript in posts plugin?

I need to add some javascript to one of the posts on my WP blog. I searched and saw that I have to put it in a separate file and refer to it from the post.
That said, it may be difficult for me to explain it to the primary user and I’m not good with Java, so I don’t want anything screwed up. Is there a 2.8 compatible plugin that will allow me to just cut and paste it in to the post. I had read about a few, but cannot find them in the plugin search.