Mon Mar 06 2017 21:23:21 GMT+0800 (CST) 渲染层错误

VM833:2 TypeError: Cannot read property ‘{{index}}’ of null

    at wfor (1040390443.debug.open.weixin.qq.com/pages/index/index.html:526)

    at _2 (1040390443.debug.open.weixin.qq.com/pages/index/index.html:610)

    at m10 (1040390443.debug.open.weixin.qq.com/pages/index/index.html:2063)

    at 1040390443.debug.open.weixin.qq.com/pages/index/index.html:3847

    at b (1040390443.debug.open.weixin.qq.com/pages/index/index.html:28)

    at k (1040390443.debug.open.weixin.qq.com/pages/index/index.html:28)

    at 1040390443.debug.open.weixin.qq.com/pages/index/index.html:28(anonymous function) @ VM833:2

VM835:1 Mon Mar 06 2017 21:23:21 GMT+0800 (CST) 渲染层错误

VM835:2 webviewScriptError

Cannot read property ‘{{index}}’ of null

TypeError: Cannot read property ‘{{index}}’ of null

    at wfor (http://1040390443.debug.open.weixin.qq.com/pages/index/index.html:526:75)

    at _2 (http://1040390443.debug.open.weixin.qq.com/pages/index/index.html:610:1)

    at m10 (http://1040390443.debug.open.weixin.qq.com/pages/index/index.html:2063:1)

    at http://1040390443.debug.open.weixin.qq.com/pages/index/index.html:3847:1

    at b (http://1040390443.debug.open.weixin.qq.com/pages/index/index.html:28:11610)

    at k (http://1040390443.debug.open.weixin.qq.com/pages/index/index.html:28:12513)

    at http://1040390443.debug.open.weixin.qq.com/pages/index/index.html:28:13257(anonymous function) @ VM835:2

VM836:1 Mon Mar 06 2017 21:23:21 GMT+0800 (CST) 渲染层错误

VM836:2 Uncaught TypeError: Cannot read property ‘{{index}}’ of null

为什么wx:for允许空值？