From 9b4d46a7c37353f6e4e41fdad22e0c7828d1bedb Mon Sep 17 00:00:00 2001
From: Robert Vrabel <rvrabel@gmail.com>
Date: Wed, 11 Jan 2017 14:05:33 -0500
Subject: [PATCH 01/13] Drum kit code added

---
 01 - JavaScript Drum Kit/index-START.html | 35 +++++++++++++++++++++--
 1 file changed, 33 insertions(+), 2 deletions(-)

diff --git a/01 - JavaScript Drum Kit/index-START.html b/01 - JavaScript Drum Kit/index-START.html
index 4070d32767..8ab322d5d8 100644
--- a/01 - JavaScript Drum Kit/index-START.html	
+++ b/01 - JavaScript Drum Kit/index-START.html	
@@ -57,9 +57,40 @@
   <audio data-key="75" src="sounds/tom.wav"></audio>
   <audio data-key="76" src="sounds/tink.wav"></audio>
 
-<script>
+  <script>
+      function playSound(e) {
+          const audio = document.querySelector(`audio[data-key="${e.keyCode}"]`);
+          const key = document.querySelector(`.key[data-key="${e.keyCode}"]`);
 
-</script>
+          // If the key pressed does exist as playable audio
+          if(!audio) {
+              return;
+          }
+
+          // Reset the audio to the start so it can be pressed multiple times
+          audio.currentTime = 0;
+
+          // Play the audio
+          audio.play();
+
+          key.classList.add('playing');
+      }
+
+      function removeTransition(e) {
+          // Check for the transform property to finish
+          if(e.propertyName !== 'transform') {
+              return;
+          }
+
+          this.classList.remove('playing');
+      }
+
+      window.addEventListener('keydown', playSound);
+
+      const keys = document.querySelectorAll('.key');
+
+      keys.forEach(key => key.addEventListener('transitionend', removeTransition));
+  </script>
 
 
 </body>

From 2fbb8d06d579d9aec8b45d61093e60150079dc06 Mon Sep 17 00:00:00 2001
From: Robert Vrabel <rvrabel@gmail.com>
Date: Wed, 11 Jan 2017 14:27:17 -0500
Subject: [PATCH 02/13] Rotate the clock

---
 02 - JS + CSS Clock/index-START.html | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/02 - JS + CSS Clock/index-START.html b/02 - JS + CSS Clock/index-START.html
index 2712384201..ebc79773fd 100644
--- a/02 - JS + CSS Clock/index-START.html	
+++ b/02 - JS + CSS Clock/index-START.html	
@@ -61,12 +61,38 @@
       background:black;
       position: absolute;
       top:50%;
+      transform-origin: 100%;
+      transform: rotate(90deg);
+      transition: all 0.05s;
+      transition-timing-function: cubic-bezier(0.06, 2.34, 0.58, 1);
     }
 
   </style>
 
   <script>
 
+  const secondHand = document.querySelector('.second-hand');
+  const minuteHand = document.querySelector('.min-hand');
+  const hourHand = document.querySelector('.hour-hand');
+
+  function setDate() {
+      const now = new Date();
+
+      const seconds = now.getSeconds();
+      const secondsDegrees = ((seconds / 60) * 360) + 90;
+      secondHand.style.transform = `rotate(${secondsDegrees}deg)`;
+
+      const mins = now.getMinutes();
+      const minsDegrees = ((mins / 60) * 360) + 90;
+      minuteHand.style.transform = `rotate(${minsDegrees}deg)`;
+
+      const hours = now.getHours();
+      const hoursDegrees = ((hours / 60) * 360) + 90;
+      hourHand.style.transform = `rotate(${hoursDegrees}deg)`;
+
+  }
+
+  setInterval(setDate, 1000);
 
   </script>
 </body>

From bfbe7a7939cd3a23f98c8a06f26615d8c5416af4 Mon Sep 17 00:00:00 2001
From: Robert Vrabel <rvrabel@gmail.com>
Date: Fri, 20 Jan 2017 11:52:14 -0500
Subject: [PATCH 03/13] Css variable video completed

---
 03 - CSS Variables/index-START.html | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/03 - CSS Variables/index-START.html b/03 - CSS Variables/index-START.html
index ca2b59d077..442042bd64 100644
--- a/03 - CSS Variables/index-START.html	
+++ b/03 - CSS Variables/index-START.html	
@@ -21,6 +21,21 @@ <h2>Update CSS Variables with <span class='hl'>JS</span></h2>
   <img src="https://source.unsplash.com/7bwQXzbF6KE/800x500">
 
   <style>
+    :root {
+        --base: #CC0000;
+        --spacing: 10px;
+        --blur: 10px;
+    }
+
+    img {
+        padding: var(--spacing);
+        background: var(--base);
+        filter: blur(var(--blur));
+    }
+
+    .h1 {
+        color: var(--base);
+    }
 
     /*
       misc styles, nothing to do with CSS variables
@@ -48,6 +63,16 @@ <h2>Update CSS Variables with <span class='hl'>JS</span></h2>
   </style>
 
   <script>
+    const inputs = document.querySelectorAll('.controls input');
+
+    function handleUpdate() {
+        const suffix = this.dataset.sizing || '';
+        document.documentElement.style.setProperty(`--${this.name}`, this.value + suffix);
+    }
+
+    inputs.forEach(input => input.addEventListener('change', handleUpdate));
+    inputs.forEach(input => input.addEventListener('mousemove', handleUpdate));
+
   </script>
 
 </body>

From d2be8fbae5ba1ebb9d15aa18600d7d110d95875e Mon Sep 17 00:00:00 2001
From: Robert Vrabel <rvrabel@gmail.com>
Date: Fri, 20 Jan 2017 14:55:18 -0500
Subject: [PATCH 04/13] Lesson 4 completed

---
 04 - Array Cardio Day 1/index-START.html | 30 +++++++++++++++++++++++-
 1 file changed, 29 insertions(+), 1 deletion(-)

diff --git a/04 - Array Cardio Day 1/index-START.html b/04 - Array Cardio Day 1/index-START.html
index eec0ffc31d..1392c71af6 100644
--- a/04 - Array Cardio Day 1/index-START.html	
+++ b/04 - Array Cardio Day 1/index-START.html	
@@ -31,29 +31,57 @@
 
     // Array.prototype.filter()
     // 1. Filter the list of inventors for those who were born in the 1500's
+    const fifteenhundreeds = inventors.filter(item => item.year > 1499 && item.year < 1600);
 
     // Array.prototype.map()
     // 2. Give us an array of the inventors' first and last names
+    const names = inventors.map(item => `${item.first} ${item.last}`);
 
     // Array.prototype.sort()
     // 3. Sort the inventors by birthdate, oldest to youngest
+    const sorted = inventors.sort((a,b) => a.year > b.year ? 1 : -1);
 
     // Array.prototype.reduce()
     // 4. How many years did all the inventors live?
+    const years = inventors.reduce((total, item) => {
+        return total + (item.passed - item.year);
+    }, 0);
 
     // 5. Sort the inventors by years lived
+    const sortedYears = inventors.sort((a,b) => (a.passed - a.year) > (b.passed - b.year) ? 1 : -1);
 
     // 6. create a list of Boulevards in Paris that contain 'de' anywhere in the name
     // https://en.wikipedia.org/wiki/Category:Boulevards_in_Paris
-
+    /*
+    const category = document.querySelector('.mw-category');
+    const links = Array.from(category.querySelectorAll('a'));
+    const de = links
+                 .map(link => link.textContent)
+                 .filter(streetName => streetName.includes('de'));
+     */
 
     // 7. sort Exercise
     // Sort the people alphabetically by last name
+    const alpha = people.sort((last, next) => {
+        const [aLast, aFirst] = last.split(', ');
+        const [bLast, bFirst] = next.split(', ');
+        return aLast > bLast ? 1 : -1;
+    });
+
 
     // 8. Reduce Exercise
     // Sum up the instances of each of these
     const data = ['car', 'car', 'truck', 'truck', 'bike', 'walk', 'car', 'van', 'bike', 'walk', 'car', 'van', 'car', 'truck' ];
 
+    const transportation = data.reduce((obj, item) => {
+        if (!obj[item]) {
+            obj[item] = 0;
+        }
+
+        obj[item]++;
+
+        return obj;
+    }, {});
   </script>
 </body>
 </html>

From 5d48ad7f2792be972b724fcc0d7fc340bac0d3aa Mon Sep 17 00:00:00 2001
From: Robert Vrabel <rvrabel@gmail.com>
Date: Fri, 20 Jan 2017 15:27:23 -0500
Subject: [PATCH 05/13] Lesson 5 completed

---
 05 - Flex Panel Gallery/index-START.html | 34 ++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/05 - Flex Panel Gallery/index-START.html b/05 - Flex Panel Gallery/index-START.html
index e1d643ad5c..7fb79ccae1 100644
--- a/05 - Flex Panel Gallery/index-START.html	
+++ b/05 - Flex Panel Gallery/index-START.html	
@@ -24,6 +24,7 @@
     .panels {
       min-height:100vh;
       overflow: hidden;
+      display: flex;
     }
 
     .panel {
@@ -41,6 +42,11 @@
       font-size: 20px;
       background-size:cover;
       background-position:center;
+      flex: 1;
+      justify-content: center;
+      align-items: center;
+      display: flex;
+      flex-direction: column;
     }
 
 
@@ -54,6 +60,20 @@
       margin:0;
       width: 100%;
       transition:transform 0.5s;
+      flex: 1 0 auto;
+      display: flex;
+      justify-content: center;
+      align-items: center;
+    }
+
+    .panel > *:first-child {
+        transform: translateY(-100%);
+    }
+    .panel.open-active > *:first-child, .panel.open-active > *:last-child {
+        transform: translateY(0);
+    }
+    .panel > *:last-child {
+        transform: translateY(100%);
     }
 
     .panel p {
@@ -67,6 +87,7 @@
     }
 
     .panel.open {
+      flex: 5;
       font-size:40px;
     }
 
@@ -107,7 +128,20 @@
   </div>
 
   <script>
+    const panels = document.querySelectorAll('.panel');
+
+    function toggleOpen() {
+        this.classList.toggle('open');
+    }
+
+    function toggleActive(e) {
+        if(e.propertyName.includes('flex')) {
+            this.classList.toggle('open-active');
+        }
+    }
 
+    panels.forEach(panel => panel.addEventListener('click', toggleOpen));
+    panels.forEach(panel => panel.addEventListener('transitionend', toggleActive));
   </script>
 
 

From df5d1655b1df603082d27676b756002567c0630c Mon Sep 17 00:00:00 2001
From: Robert Vrabel <rvrabel@gmail.com>
Date: Thu, 26 Jan 2017 14:20:21 -0500
Subject: [PATCH 06/13] Lesson 6 completed

---
 06 - Type Ahead/index-START.html | 43 +++++++++++++++++++++++++++++++-
 1 file changed, 42 insertions(+), 1 deletion(-)

diff --git a/06 - Type Ahead/index-START.html b/06 - Type Ahead/index-START.html
index 1436886918..1b818d7e84 100644
--- a/06 - Type Ahead/index-START.html	
+++ b/06 - Type Ahead/index-START.html	
@@ -15,7 +15,48 @@
     </ul>
   </form>
 <script>
-const endpoint = 'https://gist.githubusercontent.com/Miserlou/c5cd8364bf9b2420bb29/raw/2bf258763cdddd704f8ffd3ea9a3e81d25e2c6f6/cities.json';
+    const endpoint = 'https://gist.githubusercontent.com/Miserlou/c5cd8364bf9b2420bb29/raw/2bf258763cdddd704f8ffd3ea9a3e81d25e2c6f6/cities.json';
+    const cities = [];
+
+    fetch(endpoint)
+        .then(blob => blob.json())
+        .then(data => cities.push(...data));
+
+    function findMatches(wordsToMatch, cities) {
+        return cities.filter(place => {
+            const regex = RegExp(wordsToMatch, 'gi');
+
+            return place.city.match(regex) || place.state.match(regex);
+        });
+    }
+
+    function displayMatches() {
+        const matches = findMatches(this.value, cities);
+        const html = matches.map(place => {
+            const regex = new RegExp(this.value, 'gi');
+            const cityName = place.city.replace(regex, `<span class="hl">${this.value}</span>`);
+            const stateName = place.state.replace(regex, `<span class="hl">${this.value}</span>`);
+
+            return `
+                <li>
+                    <span class="name">${cityName}, ${stateName}</span>
+                    <span class="population">${numberWithCommas(place.population)}</span>
+                </li>
+            `;
+        }).join('');
+
+        suggestions.innerHTML = html;
+    }
+
+    function numberWithCommas(x) {
+      return x.toString().replace(/\B(?=(\d{3})+(?!\d))/g, ',');
+    }
+
+    const searchInput = document.querySelector('.search');
+    const suggestions = document.querySelector('.suggestions');
+
+    searchInput.addEventListener('change', displayMatches);
+    searchInput.addEventListener('keyup', displayMatches);
 
 </script>
   </body>

From a19bca321b325cb13753215b4b0f95c165831da8 Mon Sep 17 00:00:00 2001
From: Robert Vrabel <rvrabel@gmail.com>
Date: Thu, 26 Jan 2017 14:31:45 -0500
Subject: [PATCH 07/13] Lesson 7 completed

---
 07 - Array Cardio Day 2/index-START.html | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/07 - Array Cardio Day 2/index-START.html b/07 - Array Cardio Day 2/index-START.html
index 969566ff78..f5e53d756b 100644
--- a/07 - Array Cardio Day 2/index-START.html	
+++ b/07 - Array Cardio Day 2/index-START.html	
@@ -26,16 +26,26 @@
 
     // Some and Every Checks
     // Array.prototype.some() // is at least one person 19 or older?
+    const isAdult = people.some(person =>
+        ((new Date()).getFullYear() - person.year > 19)
+    );
+
     // Array.prototype.every() // is everyone 19 or older?
+    const allAdults = people.every(person => ((new Date()).getFullYear() - person.year > 19));
 
     // Array.prototype.find()
     // Find is like filter, but instead returns just the one you are looking for
     // find the comment with the ID of 823423
+    const comment = comments.find(comment => comment.id == 823423);
 
     // Array.prototype.findIndex()
     // Find the comment with this ID
     // delete the comment with the ID of 823423
-
+    const index = comments.findIndex(comment => comment.id === 823423);
+    const newComments = [
+        ...comments.slice(0, index),
+        ...comments.slice(index +1)
+    ];
   </script>
 </body>
 </html>

From a462d0c1a64977b133613f7e828ed5ddc4ae8d4f Mon Sep 17 00:00:00 2001
From: Robert Vrabel <rvrabel@gmail.com>
Date: Thu, 26 Jan 2017 15:13:34 -0500
Subject: [PATCH 08/13] Lesson 8 completed

---
 08 - Fun with HTML5 Canvas/index-START.html | 52 +++++++++++++++++++++
 1 file changed, 52 insertions(+)

diff --git a/08 - Fun with HTML5 Canvas/index-START.html b/08 - Fun with HTML5 Canvas/index-START.html
index 37c148df07..3b2b87fbc1 100644
--- a/08 - Fun with HTML5 Canvas/index-START.html	
+++ b/08 - Fun with HTML5 Canvas/index-START.html	
@@ -7,6 +7,58 @@
 <body>
 <canvas id="draw" width="800" height="800"></canvas>
 <script>
+    const canvas = document.querySelector('#draw');
+    const ctx = canvas.getContext('2d');
+    canvas.width = window.innerWidth;
+    canvas.height = window.innerHeight;
+    ctx.strokeStyle = '#BADA55';
+    ctx.lineJoin = 'round';
+    ctx.lineCap = 'round';
+    ctx.lineWidth = 100;
+
+    let isDrawing = false;
+    let lastX = 0;
+    let lastY = 0;
+    let hue = 0;
+    let direction = true;
+
+    function draw(e) {
+        if(!isDrawing) {
+            return;
+        }
+
+        ctx.strokeStyle = `hsl(${hue}, 100%, 50%)`;
+        ctx.beginPath();
+        ctx.moveTo(e.offsetX, e.offsetY);
+        ctx.lineTo(e.offsetX, e.offsetY);
+        ctx.stroke();
+
+        [lastX, lastY] = [e.offsetX, e.offsetY];
+
+        hue++;
+        if(hue >= 360) {
+            hue = 0;
+        }
+
+        if(ctx.lineWidth >= 100 || ctx.lineWidth <= 1) {
+             direction = !direction;
+        }
+
+        if(direction) {
+            ctx.lineWidth++;
+        }else{
+            ctx.lineWidth--;
+        }
+    }
+
+    canvas.addEventListener('mousemove', draw);
+    canvas.addEventListener('mousedown', (e) => {
+      isDrawing = true;
+      [lastX, lastY] = [e.offsetX, e.offsetY];
+    });
+    canvas.addEventListener('mouseup', () => isDrawing = false);
+    canvas.addEventListener('mouseout', () => isDrawing = false);
+
 </script>
 
 <style>

From c42517390d3387dda2ab8a24a5477b071dbaf279 Mon Sep 17 00:00:00 2001
From: Robert Vrabel <rvrabel@gmail.com>
Date: Thu, 26 Jan 2017 15:28:59 -0500
Subject: [PATCH 09/13] Lesson 9 completed

---
 09 - Dev Tools Domination/index-START.html | 29 ++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/09 - Dev Tools Domination/index-START.html b/09 - Dev Tools Domination/index-START.html
index 196fffd719..382abfabfe 100644
--- a/09 - Dev Tools Domination/index-START.html	
+++ b/09 - Dev Tools Domination/index-START.html	
@@ -18,28 +18,57 @@
     }
 
     // Regular
+    console.log('test');
 
     // Interpolated
+    console.log('My String %s', 'var');
 
     // Styled
+    console.log('%c', 'font-size: ');
 
     // warning!
+    console.warn('Warning!');
 
     // Error :|
+    console.error('Error!');
 
     // Info
+    console.info('Info!');
 
     // Testing
+    console.assert(1 === 2);
 
     // clearing
+    console.clear();
 
     // Viewing DOM Elements
+    console.dir(document.querySelector('p'));
 
     // Grouping together
+    dogs.forEach(dog => {
+        console.groupCollapsed(`${dog.name}`);
+        console.log(`This is ${dog.name}`);
+        console.log(`${dog.name} is ${dog.age} years old`);
+        console.log(`${dog.name} is ${dog.age * 7} dog years old`);
+        console.groupEnd(`${dog.name}`);
+    });
 
     // counting
+    console.count('Test1');
+    console.count('Test2');
+    console.count('Test1');
+    console.count('Test1');
 
     // timing
+    console.time('fetching data');
+        fetch('https://api.github.com/users/wesbos')
+        .then(data => data.json())
+        .then(data => {
+            console.timeEnd('fetching data');
+            console.log(data);
+        });
+
+      console.table(dogs);
 
   </script>
 </body>

From a8861940cd53f0d987c654c83b537f9ae97b7fb4 Mon Sep 17 00:00:00 2001
From: Robert Vrabel <al2604@wayne.edu>
Date: Wed, 15 Feb 2017 13:19:51 -0500
Subject: [PATCH 10/13] lesson 10 completed

---
 .../index-START.html                          | 23 +++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/10 - Hold Shift and Check Checkboxes/index-START.html b/10 - Hold Shift and Check Checkboxes/index-START.html
index b6a1cc32ec..2e721c8fd5 100644
--- a/10 - Hold Shift and Check Checkboxes/index-START.html	
+++ b/10 - Hold Shift and Check Checkboxes/index-START.html	
@@ -104,6 +104,29 @@
   </div>
 
 <script>
+    const checkboxes = document.querySelectorAll('.inbox input[type="checkbox"]');
+
+    let lastChecked;
+
+    function handleCheck(e) {
+        let inBetween = false;
+
+        if(e.shiftKey && this.checked) {
+            checkboxes.forEach(checkbox => {
+                if(checkbox == this || checkbox == lastChecked) {
+                    inBetween = !inBetween;
+                }
+
+                if(inBetween) {
+                    checkbox.checked = true;
+                }
+            });
+        }
+
+        lastChecked = this;
+    }
+
+    checkboxes.forEach(checkbox => checkbox.addEventListener('click', handleCheck));
 </script>
 </body>
 </html>

From 7ceb249ee0782d33c575160d22a9680053c1fb42 Mon Sep 17 00:00:00 2001
From: Robert Vrabel <al2604@wayne.edu>
Date: Wed, 15 Feb 2017 13:58:46 -0500
Subject: [PATCH 11/13] Lesson 11 completed

---
 11 - Custom Video Player/scripts.js | 53 +++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)

diff --git a/11 - Custom Video Player/scripts.js b/11 - Custom Video Player/scripts.js
index e69de29bb2..3ca20fbe55 100644
--- a/11 - Custom Video Player/scripts.js	
+++ b/11 - Custom Video Player/scripts.js	
@@ -0,0 +1,53 @@
+// Elements
+const player = document.querySelector('.player');
+const video = player.querySelector('.viewer');
+const progress = player.querySelector('.progress');
+const progressBar = player.querySelector('.progress__filled');
+const toggle = player.querySelector('.toggle');
+const skipButtons = player.querySelectorAll('[data-skip]');
+const ranges = player.querySelectorAll('.player__slider');
+
+// Functions
+function togglePlay() {
+  const method = video.paused ? 'play' : 'pause';
+  video[method]();
+}
+
+function updateButton() {
+  const icon = this.paused ? '►' : '❚ ❚';
+  console.log(icon);
+  toggle.textContent = icon;
+}
+
+function skip() {
+    video.currentTime += parseFloat(this.dataset.skip);
+}
+
+function handleRangeUpdate() {
+    video[this.name] = this.value;
+}
+
+function handleProgress() {
+    const percent = (video.currentTime / video.duration) * 100;
+    progressBar.style.flexBasis = `${percent}%`;
+}
+
+function scrub(e) {
+    const scrubTime = (e.offsetX / progress.offsetWidth) * video.duration;
+    video.currentTime = scrubTime;
+}
+
+// Listeners
+video.addEventListener('click', togglePlay);
+video.addEventListener('play', updateButton);
+video.addEventListener('pause', updateButton);
+video.addEventListener('timeupdate', handleProgress);
+skipButtons.forEach(button => button.addEventListener('click', skip));
+ranges.forEach(range => range.addEventListener('change', handleRangeUpdate));
+ranges.forEach(range => range.addEventListener('mousemove', handleRangeUpdate));
+
+let mousedown = false;
+progress.addEventListener('click', scrub);
+progress.addEventListener('mousemove', (e) => mousedown && scrub(e));
+progress.addEventListener('mousedown', () => mousedown = true);
+progress.addEventListener('mouseup', () => mousedown = false);

From d57882b5b3c9b076a235ec3198108ddb81eec6fe Mon Sep 17 00:00:00 2001
From: Robert Vrabel <al2604@wayne.edu>
Date: Mon, 20 Feb 2017 14:42:11 -0500
Subject: [PATCH 12/13] Lesson 12 completed

---
 12 - Key Sequence Detection/index-START.html | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/12 - Key Sequence Detection/index-START.html b/12 - Key Sequence Detection/index-START.html
index 8cab786140..38c9fe2949 100644
--- a/12 - Key Sequence Detection/index-START.html	
+++ b/12 - Key Sequence Detection/index-START.html	
@@ -7,6 +7,18 @@
 </head>
 <body>
 <script>
+const pressed = [];
+const secretCode = 'rob';
+
+window.addEventListener('keyup', (e) => {
+    pressed.push(e.key);
+    pressed.splice(-secretCode.length - 1, pressed.length - secretCode.length);
+
+    if(pressed.join('').includes(secretCode)) {
+        console.log('secret found!');
+        cornify_add();
+    }
+});
 </script>
 </body>
 </html>

From c08c6d07cb9de96662e9ef3078f43518138a7e7e Mon Sep 17 00:00:00 2001
From: Robert Vrabel <al2604@wayne.edu>
Date: Mon, 20 Feb 2017 15:18:38 -0500
Subject: [PATCH 13/13] Lesson 13 completed

---
 13 - Slide in on Scroll/index-START.html | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/13 - Slide in on Scroll/index-START.html b/13 - Slide in on Scroll/index-START.html
index 0b9fb8fccb..b0d5b3cb7d 100644
--- a/13 - Slide in on Scroll/index-START.html	
+++ b/13 - Slide in on Scroll/index-START.html	
@@ -58,6 +58,27 @@ <h1>Slide in on Scroll</h1>
       };
     }
 
+    const sliderImages = document.querySelectorAll('.slide-in');
+
+    function checkSlide(e) {
+        sliderImages.forEach(sliderImage => {
+            // Half way through the image
+            const slideInAt = (window.scrollY + window.innerHeight) - sliderImage.height / 2;
+
+            // Bottom of the image
+            const imageBottom = sliderImage.offsetTop + sliderImage.height;
+            const isHalfShown = slideInAt > sliderImage.offsetTop;
+            const isNotScrolledPast = window.scrollY < imageBottom;
+
+            if (isHalfShown && isNotScrolledPast) {
+                sliderImage.classList.add('active');
+            } else {
+                sliderImage.classList.remove('active');
+            }
+        });
+    }
+
+    window.addEventListener('scroll', debounce(checkSlide));
   </script>
 
   <style>