R Markdown Presentation不加载/渲染交互式Plotly图表

Question

我正在使用Plotly with R创建一个将在R Markdown Presentation With Ioslides中呈现的图表，而不是像下面那样显示the demo chart from the website：

它正在呈现这样的步骤：

我的代码非常简单：

---
title: "R Markdown Presentation & Plotly"
author: "Eduardo Almeida"
date: "February 19, 2017"
output: ioslides_presentation
---

```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = FALSE)
```

## Interactive plot with Plotly 

```{r}
library(plotly)
p <- plot_ly(economics, x = ~date, y = ~unemploy / pop)
```