Javascript in Eclipse

The problem: In Eclipse on my Windows machine at work, I get an error attempting to open Javascript files, and have to open them as plain text.

After a bit of Googling around, I ended up using the JSEditor plugin. There doesn't seem to be an update site for it, so I downloaded it from

http://sourceforge.net/projects/jseditor/

To install it, cd into the eclipse directory (with the 'plugins' subdir), and unzip it. Then restart Eclipse.