小程序input输入框第二次失去焦点时会报错

如何看待微信公开课小程序热门讨论「小程序input输入框第二次失去焦点时会报错」
摘要：小程序input输入框第二次失去焦点时会报错
展开：input输入框当value为空的时候失去焦点第一次不报错当再次触发失去焦点不管value是不是为空都会报错！哪位大神能给解决下！小弟刚开始接触，不太懂！报错代码：thirdScriptErrorthis[n].applyisnotafunction;atpages/component/second/indexpageuserNamefunctionTypeError:this[n].applyisnotafunctionate.a(http://70502904.appservice.open.weixin.qq.com/WAService.js:8:27066)atR(http://70502904.appservice.open.weixin.qq.com/WAService.js:8:22530)at.anonymous(http://70502904.appservice.open.weixin.qq.com/WAService.js:8:23963)athttp://70502904.appservice.open.weixin.qq.com/WAService.js:8:28571athttp://70502904.appservice.open.weixin.qq.com/WAService.js:4:4856atObject.e.(anonymousfunction)[asPAGE_EVENT](http://70502904.appservice.open.weixin.qq.com/WAService.js:4:18109)atn.anonymous(http://70502904.appservice.open.weixin.qq.com/asdebug.js:1:13708)atn.emit(http://70502904.appservice.open.weixin.qq.com/asdebug.js:1:8747)atr(http://70502904.appservice.open.weixin.qq.com/asdebug.js:1:1385)athttp://70502904.appservice.open.weixin.qq.com/asdebug.js:1:4867errorReport@WAService.js:3thirdErrorReport@WAService.js:3(anonymousfunction)@WAService.js:3a@WAService.js:8R@WAService.js:8(anonymousfunction)@WAService.js:8(anonymousfunction)@WAService.js:8(anonymousfunction)@WAService.js:4e.(anonymousfunction)@WAService.js:4(anonymousfunction)@asdebug.js:1n.emit@asdebug.js:1r@asdebug.js:1(anonymousfunction)@asdebug.js:1g@asdebug.js:1(anonymousfunction)@asdebug.js:1相关源码htmlinputtypetextplaceholder会员姓名bindbluruserName/jsuserName:function(e){this.userNamee.detail.value;}变量都已经声明过了