By clicking this arrow you will tell the system to enable the Java plug-in, but will have to quit and relaunch your Web browser in order for it to work.

To view our interactive tools properly, you need to be using a Java-enabled browser (Microsoft Internet Explorer v. 3 or above, or Netscape v. 3 or above), preferably on a Windows 95 and higher ...

To enable JavaScript, go into the Settings app on your iPhone, click "Safari," then "Advanced," and swipe the JavaScript button to the right so it appears green. Here's a full breakdown with pictures.