The JavaScript Programming Language links are redundant, but I’ll leave them in for convenience.
If you don’t know — you can simply paste these links into Safari’s download sheet, and they will be queued for download.
I generally use Leech.app for such things me’self. It’s a lightweight and quite scriptable downloader.
http://yui.zenfs.com/theater/crockford-advancedjavascript-1.m4v
http://yui.zenfs.com/theater/crockford-advancedjavascript-2.m4v
http://yui.zenfs.com/theater/crockford-advancedjavascript-3.m4v
http://yui.zenfs.com/theater/crockford-domtheory-1.m4v
http://yui.zenfs.com/theater/crockford-domtheory-2.m4v
http://yui.zenfs.com/theater/crockford-domtheory-3.m4v
http://yui.zenfs.com/theater/crockford-tjpl-1.m4v
http://yui.zenfs.com/theater/crockford-tjpl-2.m4v
http://yui.zenfs.com/theater/crockford-tjpl-3.m4v
http://yui.zenfs.com/theater/crockford-tjpl-4.m4v
The YouTube link JM posted I believe is the full-length version of “The JavaScript Programming Language”, and that is easy enough to download with Firefox and the FlashGot extension or another YouTube downloader.
I generally use the youtube-dl command-line-tool + an AppleScript to pick the version I want + the Terminal for progress-info and feedback.
-Chris