Declare important cc namespace and JSLint

cocos2d-x JavaScript
#1

Hi. Thans for your tutorial.
Why important cc namespace declare:
var cc = cc = cc || {};
this declaration isn’t valid with JSLint.
This declaration is valid for JSLint:
var cc = cc || {};

#2

There is a bug in ie, that sometimes var cc = cc || {} does not as expected,

var cc = cc = cc || {}; is a hack for ie (which version? i forgot)

it might be a hack for IE version lower than 9, but just in case.