[Vue warn]: Property or method "content" is not defined on the instance but referenced during render.? Make sure that this property is reactive, either in the data option, or for class-based components, by initializing the property.? See: https://v2.vuejs.org/v2/guide/reactivity.html#Declaring-Reactive-Properties.

屬性或方法“content”不是在實例上定義的，而是在渲染期間引用的。通過初始化屬性，確保該屬性是可響應的，無論是在data選項中，還是對于基于類的組件。見:https://v2.vuejs.org/v2/guide/reactivity.html Declaring-Reactive-Properties。