diff --git a/index.html b/index.html
index 3415d7385..b9974881c 100644
--- a/index.html
+++ b/index.html
@@ -41,3 +41,5 @@ <h3>Splits</h3>
     <script src="javascript/index.js"></script>
   </body>
 </html>
+
+<button></button>
diff --git a/javascript/chronometer.js b/javascript/chronometer.js
index 7a1349680..4368db5e6 100644
--- a/javascript/chronometer.js
+++ b/javascript/chronometer.js
@@ -1,34 +1,44 @@
 class Chronometer {
   constructor() {
-    // ... your code goes here
+    this.currentTime = 0;
+    this.intervalId = null;
   }
 
   start(callback) {
-    // ... your code goes here
+    this.intervalId = setInterval (() => {
+      this.currentTime += 1;
+      if (callback) callback();
+    }, 10);
   }
 
   getMinutes() {
-    // ... your code goes here
+    return Math.floor(this.currentTime / 6000);
   }
 
   getSeconds() {
-    // ... your code goes here
+    return Math.floor(this.currentTime / 100) % 60;
+  }
+
+  getMilliseconds () {
+    return this.currentTime % 100;
   }
 
   computeTwoDigitNumber(value) {
-    // ... your code goes here
+    return value.toString().padStart(2, '0');
   }
 
   stop() {
-    // ... your code goes here
+    clearInterval(this.intervalId);
   }
 
   reset() {
-    // ... your code goes here
+    this.currentTime = 0;
   }
 
   split() {
-    // ... your code goes here
+    const minutes = this.computeTwoDigitNumber(this.getMinutes());
+    const seconds = this.computeTwoDigitNumber(this.getSeconds());
+    return `${minutes}:${seconds}`;
   }
 }
 
diff --git a/javascript/index.js b/javascript/index.js
index fb3a43ab4..4937b4759 100644
--- a/javascript/index.js
+++ b/javascript/index.js
@@ -14,52 +14,81 @@ const milUniElement = document.getElementById('milUni');
 const splitsElement = document.getElementById('splits');
 
 function printTime() {
-  // ... your code goes here
+  printMinutes();
+  printSeconds();
+  printMilliseconds();
 }
 
 function printMinutes() {
-  // ... your code goes here
+  const minutes = chronometer.computeTwoDigitNumber(chronometer.getMinutes());
+  minDecElement.innerText = minutes[0];
+  minUniElement.innerText = minutes[1];
 }
 
 function printSeconds() {
-  // ... your code goes here
+  const seconds = chronometer.computeTwoDigitNumber(chronometer.getSeconds());
+  secDecElement.innerText = seconds[0];
+  secUniElement.innerText = seconds[1];
 }
 
 // ==> BONUS
 function printMilliseconds() {
-  // ... your code goes here
+  const ms = chronometer.computeTwoDigitNumber(chronometer.getMilliseconds());
+  milDecElement.innerText = ms[0];
+  milUniElement.innerText = ms[1];
 }
 
 function printSplit() {
-  // ... your code goes here
+  const li = document.createElement('li');
+  li.className = 'list-item';
+  li.innerText = chronometer.split();
+  splitsElement.appendChild(li);
 }
 
 function clearSplits() {
-  // ... your code goes here
+  splitsElement.innerHTML = '';
 }
 
 function setStopBtn() {
-  // ... your code goes here
+  btnLeftElement.className = 'btn stop';
+  btnLeftElement.innerText = 'STOP';
 }
 
 function setSplitBtn() {
-  // ... your code goes here
+  btnRightElement.className = 'btn split';
+  btnRightElement.innerText = 'SPLIT';
 }
 
 function setStartBtn() {
-  // ... your code goes here
+  btnLeftElement.className = 'btn start';
+  btnLeftElement.innerText = 'START';
 }
 
 function setResetBtn() {
-  // ... your code goes here
+  btnRightElement.className = 'btn reset';
+  btnRightElement.innerText = 'RESET';
 }
 
 // Start/Stop Button
 btnLeftElement.addEventListener('click', () => {
-  // ... your code goes here
+  if (btnLeftElement.classList.contains('start')) {
+    chronometer.start(printTime);
+    setStopBtn();
+    setSplitBtn();
+  } else {
+    chronometer.stop();
+    setStartBtn();
+    setResetBtn();
+  }
 });
 
 // Reset/Split Button
 btnRightElement.addEventListener('click', () => {
-  // ... your code goes here
+  if (btnRightElement.classList.contains('reset')) {
+    chronometer.reset();
+    printTime();
+    clearSplits();
+  } else {
+    printSplit();
+  }
 });