diff --git a/Sprint-3/alarmclock/alarmclock.js b/Sprint-3/alarmclock/alarmclock.js
index 6ca81cd3b..be1db5206 100644
--- a/Sprint-3/alarmclock/alarmclock.js
+++ b/Sprint-3/alarmclock/alarmclock.js
@@ -1,4 +1,39 @@
-function setAlarm() {}
+// Turns a number of seconds into "MM:SS" format
+// e.g. 75 -> "01:15"
+function formatTime(seconds) {
+ const minutes = Math.floor(seconds / 60);
+ const remainingSeconds = seconds % 60;
+
+ // padStart makes sure single digits get a leading zero e.g. 5 -> "05"
+ const mm = String(minutes).padStart(2, "0");
+ const ss = String(remainingSeconds).padStart(2, "0");
+
+ return mm + ":" + ss;
+}
+
+function setAlarm() {
+ // Get the number the user typed in the input field
+ let seconds = Number(document.getElementById("alarmSet").value);
+
+ // Update the heading to show the starting time
+ document.getElementById("timeRemaining").innerText =
+ "Time Remaining: " + formatTime(seconds);
+
+ // Count down every 1000ms (1 second)
+ let intervalId = setInterval(function () {
+ seconds = seconds - 1;
+
+ // Update the heading each second
+ document.getElementById("timeRemaining").innerText =
+ "Time Remaining: " + formatTime(seconds);
+
+ // When we reach zero, stop counting and play the alarm
+ if (seconds === 0) {
+ clearInterval(intervalId);
+ playAlarm();
+ }
+ }, 1000);
+}
// DO NOT EDIT BELOW HERE
diff --git a/Sprint-3/alarmclock/index.html b/Sprint-3/alarmclock/index.html
index 48e2e80d9..328e06582 100644
--- a/Sprint-3/alarmclock/index.html
+++ b/Sprint-3/alarmclock/index.html
@@ -1,20 +1,23 @@
-
-
-
-
- Title here
-
-
-