0004 added[hypotenuseCalculator, counter, randomNumberGeneration]

js/counter.js

@@ -0,0 +1,17 @@
+//My approach
+
+document.getElementById("countDownButton").onclick = function() {
+    let i = Number.parseInt(document.getElementById("counter").innerHTML);
+    i--;
+    document.getElementById("counter").innerHTML = i;
+}
+
+document.getElementById("resetButton").onclick = function() {
+    document.getElementById("counter").innerHTML = 0;
+}
+
+document.getElementById("countUpButton").onclick = function() {
+    let i = Number.parseInt(document.getElementById("counter").innerHTML);
+    i++;
+    document.getElementById("counter").innerHTML = i;
+}