support item data default is function
support item data default is function

akira-cn/thinkjs,akira-cn/thinkjs,maxzhang/thinkjs,75team/thinkjs,snadn/thinkjs,75team/thinkjs,Qihoo360/thinkjs,thinkjs/thinkjs,75team/thinkjs,maxzhang/thinkjs,akira-cn/thinkjs,maxzhang/thinkjs