diff --git a/README.md b/README.md
index c05b0617..795b02a2 100644
--- a/README.md
+++ b/README.md
@@ -29,7 +29,7 @@ If you want to spin up an instance and start using immediately, see [Docker depl
 If you want to contribute to the project, start with [manual deployment](https://hackmd.io/c/codimd-documentation/%2Fs%2Fcodimd-manual-deployment).
 
 ### Configuration
-CodiMD is highly customizable. Learn about all configuration options of networking, security, performance, resources, privilege, privacy, image storage, and authentication in [CodiMD Configuration](https://hackmd.io/c/codimd-documentation/%2Fs%2Fcodimd-configuration).
+CodiMD is highly customizable, learn about all configuration options of networking, security, performance, resources, privilege, privacy, image storage, and authentication in [CodiMD Configuration](https://hackmd.io/c/codimd-documentation/%2Fs%2Fcodimd-configuration).
 
 ### Upgrading and Migration
 Upgrade CodiMD from previous version? See [this guide](https://hackmd.io/c/codimd-documentation/%2Fs%2Fcodimd-upgrade)
diff --git a/public/build/reveal.js/plugin/elapsed-time-bar/elapsed-time-bar.js b/public/build/reveal.js/plugin/elapsed-time-bar/elapsed-time-bar.js
new file mode 100644
index 00000000..0d7e8b93
--- /dev/null
+++ b/public/build/reveal.js/plugin/elapsed-time-bar/elapsed-time-bar.js
@@ -0,0 +1,144 @@
+var ElapsedTimeBar = {
+  // default value
+  barColor: 'rgb(200,0,0)',
+  pausedBarColor: 'rgba(200,0,0,.6)',
+
+  isPaused: false,
+  isFinished: false,
+
+  allottedTime: null,
+  timeProgressBar: null,
+  startTime: null,
+  pauseTime: null,
+  pauseTimeDuration: 0,
+
+  /**
+   * initialize elements
+   */
+  handleReady() {
+    var config = Reveal.getConfig();
+
+    // activate this plugin if config.allottedTime exists.
+    if (!config.allottedTime) {
+      console.warn('Failed to start ElapsedTimeBar plugin. "allottedTime" property is required.');
+      return;
+    }
+
+    // set configurations
+    this.barColor = config.barColor || this.barColor;
+    this.pausedBarColor = config.pausedBarColor || this.pausedBarColor;
+
+    // calc barHeight from config.barHeight or page-progress container
+    var barHeight;
+    var pageProgressContainer = document.querySelector('.progress');
+    if (config.progressBarHeight) {
+      barHeight = parseInt(config.progressBarHeight, 10) + 'px';
+
+      // override height of page-progress container
+      pageProgressContainer && (pageProgressContainer.style.height = barHeight);
+    } else if (config.progress && pageProgressContainer) {
+      // get height from page-progress container
+      barHeight = pageProgressContainer.getBoundingClientRect().height + 'px';
+    } else {
+      // default
+      barHeight = '3px';
+    }
+
+    // create container of time-progress
+    var timeProgressContainer = document.createElement('div');
+    timeProgressContainer.classList.add('progress');
+    Object.entries({
+      display: 'block',
+      position: 'fixed',
+      bottom: config.progress ? barHeight : 0,
+      width: '100%',
+      height: barHeight
+    }).forEach(([k, v]) => {
+      timeProgressContainer.style[k] = v;
+    });
+    document.querySelector('.reveal').appendChild(timeProgressContainer);
+
+    // create content of time-progress
+    this.timeProgressBar = document.createElement('div');
+    Object.entries({
+      height: '100%',
+      willChange: 'width'
+    }).forEach(([k, v]) => {
+      this.timeProgressBar.style[k] = v;
+    });
+    timeProgressContainer.appendChild(this.timeProgressBar);
+
+    // start timer
+    this.start(config.allottedTime);
+  },
+
+  /**
+   * update repeatedly using requestAnimationFrame.
+   */
+  loop() {
+    if (this.isPaused) return;
+    var now = +new Date();
+    var elapsedTime = now - this.startTime - this.pauseTimeDuration;
+    if (elapsedTime > this.allottedTime) {
+      this.timeProgressBar.style.width = '100%';
+      this.isFinished = true;
+    } else {
+      this.timeProgressBar.style.width = elapsedTime / this.allottedTime * 100 + '%';
+      requestAnimationFrame(this.loop.bind(this));
+    }
+  },
+
+  /**
+   * set color of progress bar
+   */
+  setBarColor() {
+    if (this.isPaused) {
+      this.timeProgressBar.style.backgroundColor = this.pausedBarColor;
+    } else {
+      this.timeProgressBar.style.backgroundColor = this.barColor;
+    }
+  },
+
+  /**
+   * start(reset) timer with new allotted time.
+   * @param {number} allottedTime
+   * @param {number} [elapsedTime=0]
+   */
+  start(allottedTime, elapsedTime = 0) {
+    this.isFinished = false;
+    this.isPaused = false;
+    this.allottedTime = allottedTime;
+    this.startTime = +new Date() - elapsedTime;
+    this.pauseTimeDuration = 0;
+    this.setBarColor();
+    this.loop();
+  },
+
+  reset() {
+    this.start(this.allottedTime);
+  },
+
+  pause() {
+    if (this.isPaused) return;
+    this.isPaused = true;
+    this.pauseTime = +new Date();
+    this.setBarColor();
+  },
+
+  resume() {
+    if (!this.isPaused) return;
+
+    // add paused time duration
+    this.isPaused = false;
+    this.pauseTimeDuration += new Date() - this.pauseTime;
+    this.pauseTime = null;
+    this.setBarColor();
+    this.loop();
+  }
+};
+
+if (Reveal.isReady()) {
+  ElapsedTimeBar.handleReady();
+} else {
+  Reveal.addEventListener('ready', () => ElapsedTimeBar.handleReady());
+}
diff --git a/public/js/slide.js b/public/js/slide.js
index 0993e9b2..d3019842 100644
--- a/public/js/slide.js
+++ b/public/js/slide.js
@@ -77,7 +77,16 @@ var options = meta.slideOptions || {}
 if (options.hasOwnProperty('spotlight')) {
   defaultOptions.dependencies.push({
     src: `${serverurl}/build/reveal.js/plugin/spotlight/spotlight.js`
-  });
+  })
+}
+
+if (options.hasOwnProperty('allottedTime') || options.hasOwnProperty('allottedMinutes')) {
+  defaultOptions.dependencies.push({
+    src: `${serverurl}/build/reveal.js/plugin/elapsed-time-bar/elapsed-time-bar.js`
+  })
+  if (options.hasOwnProperty('allottedMinutes')) {
+    options.allottedTime = options.allottedMinutes * 60 * 1000
+  }
 }
 
 const view = $('.reveal')