fix demo bug
fix demo bug

ekinwei/zrender,powy1993/zrender,KnightBubble/zrender,jl9n/zrender,dato-code/zrender,dasmond/zrender,skyujilong/zrender,songshuang00/zrender,powy1993/zrender,nagyistoce/ecomfe-zrender,laomu1988/zrender,IveWong/zrender,laomu1988/zrender,coderstudy/zrender,ChaosPower/zrender,elancom/zrender,ecomfe/zrender,dato-code/zrender,powy1993/zrender,noikiy/zrender,IveWong/zrender,dasmond/zrender,skyujilong/zrender,ecomfe/zrender,stanleyxu2005/zrender,armslave00/zrender,uooo/zrender,noikiy/zrender,lkiarest/zrender,KnightBubble/zrender,ilovezy/zrender,ekinwei/zrender,ecomfe/zrender,jl9n/zrender,nagyistoce/ecomfe-zrender,uooo/zrender,elancom/zrender,songshuang00/zrender,coderstudy/zrender,ilovezy/zrender,armslave00/zrender,lkiarest/zrender,stanleyxu2005/zrender,ChaosPower/zrender