Question : Any good advanced javascript books/links to recommend?

I have some basic knowledge of javascript before, but I found I can't understand well below javascript source code:

 read : {
       dwrFunction : DwrInterface.read,

Could anyone tell me what the colon stands for in below script?
xxx:function()...

Any good advanced javascript books/links to recommend (especially on OOP, events, etc.)? Thanks a lot.

Answer : Any good advanced javascript books/links to recommend?

My favorite (and I own it) "Professional JavaScript for Web Developers"

http://www.amazon.co.uk/Professional-JavaScript-Developers-Wrox-Guides/dp/0764579088

My favorite online resource due to the plethora of practical examples: http://www.irt.org/