Create ex4

Chapter 11/ex4

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+        const endDate = "Sept 1 2022";
+        update();
+        function update() {
+            const temp = countdown();
+            for (const property in temp) {
+                console.log(`${property}: ${temp[property]}`);
+            }
+            window.setTimeout(update, 1000);
+        }
+        function countdown() {
+            const total = Date.parse(endDate) - Date.parse(new Date());
+            const seconds = Math.floor((total / 1000) % 60);
+            const minutes = Math.floor((total / 1000 / 60) % 60);
+            const hours = Math.floor((total / (1000 * 60 * 60)) % 24);
+            const days = Math.floor(total / (1000 * 60 * 60 * 24));
+            return {
+                total,
+                days,
+                hours,
+                minutes,
+                seconds
+            };
+        }