How to get smooth seeking/scrubbing in VideoJS?

When scrubbing on the example video on the front page of the VideoJS site (http://videojs.com/), at first, the frame that has been seeked will take a second to load, but if you re-seek to that frame after it has loaded, it will be smooth and seamless and the video will show that frame immediately. So if you have scrubbed through enough frames, eventually, the scrubbing experience will be completely smooth without any loading pauses. This is what I'm trying to achieve.

In all my efforts to use VideoJS, I have not been able to achieve this. I don't know what I'm doing wrong. I have set "preload" to true. I have scoured the documentation for information about local caching of the frames, and there is nothing. How do I get my browser to cache the video frames as they are seeked so that if I seek back to them, they appear immediately from the cache instead of being reloaded?