Fix beeper to work even today off-tab

src/resources/beeping/main.js

@@ -4,6 +4,7 @@ var beepTimeCounter = 0;
 var intervalId = 0;
 var timeChangedWhileBegun = false;
 var lastSec = -1;
+var lastTimestampMs = 0;
 
 var showBeep = 0;
 
@@ -114,6 +115,7 @@ function toggle() {
     beeperBegun = !beeperBegun;
     if (beeperBegun) {
         button.innerText = "Stop!";
+        lastTimestampMs = Date.now();
         intervalId = setInterval(update, 10);
     } else {
         button.innerText = "Begin!";
@@ -134,9 +136,14 @@ function update() {
     var seconds = document.getElementById("seconds");
     var milliseconds = document.getElementById("milliseconds");
 
-    beepTimeCounter -= 0.01;
-    showBeep -= 0.1;
+    var currentTimestampMs = Date.now();
+    var delta = currentTimestampMs - lastTimestampMs;
+    lastTimestampMs = currentTimestampMs;
+
+    beepTimeCounter -= (delta / 1000);
+    showBeep -= (delta / 1000);
     if (beepTimeCounter <= 0) {
+        console.log(beepTimeCounter);
         beepTimeCounter = beepInterval;
         showBeep = 0.5;
         document.getElementById("audio").fastSeek(0)
@@ -154,7 +161,7 @@ function update() {
         if (showBeep > 0) {
             document.title = "Beeeep!";
         } else {
-            document.title = "Beeper - " + sec;
+            document.title = "Beeper | " + sec;
         }
     }
 }