An issue I see with legend symbology in AGS JS TOC is it does not work in IE for secured services.  We a service on ArcGIS Server 10.0 coming in to the JS API 3.3 viewer with newest AGS JS TOC widget code and see this. I called ESRI, they know about it, it has a NIM. It's something about how IE can't get bitmaps as pieces of text or something obscure, I forget.  But it works in all other browsers.  Just wondering if anyone found a way around this IE bug?   Perhaps it will work if we put the service on Server 10.1 with the legend features?  Although we'll be on 10.0 for a while. 
Nianwei thank you again, your code and the documentation are great.  I would love to see ESRI officially include your AGS JS TOC widget into the API!!