added bomb falling, collision, and animation logic

game.html

@@ -42,5 +42,6 @@
 		
 		
 
+
 	</body>
 </html>

scripts/enemy.js

@@ -1,10 +1,12 @@
 /* enemy spawning logic */
 var aliens = [];
+var bombs = [];
 
 function spawnEnemy() {
    var alien = document.createElement("div");
    alien.className = "alien";
    alien.id = "alien";
+   alien.style.zIndex = "2"
    while (true) {
         alien.style.left = Math.floor(Math.random() * document.body.offsetWidth) + "px";
         if (document.elementFromPoint(alien.offsetLeft, alien.offsetTop).classList.contains("alien") == false) {   
@@ -16,11 +18,28 @@ function spawnEnemy() {
 }
 
 function spawnBomb() {
-    var alien = aliens[0];
+    var alien = aliens[Math.floor(Math.random() * aliens.length)];
     var bomb = document.createElement("div");
     bomb.className = "bomb";
     bomb.style.left = "28px";
     bomb.style.top = "70px";
-    bomb.style.zIndex = "-1";
+    bomb.style.zIndex = "1";
+    bomb.style.display = "absolute";
     alien.appendChild(bomb);
+    bombLogic = setInterval(fall, 100);
+    bombs.push([bomb, bombLogic]);
+}
+
+function fall() {
+    var bomb = bombs[Math.floor(Math.random() * bombs.length)];
+    bomb[0].style.top = (bomb[0].offsetTop + 10) + "px";
+
+    for (let element of bombs) {
+        if (document.elementFromPoint(element[0].offsetLeft, element[0].offsetTop).classList.contains("sky") != true) {
+            if(Math.floor(Math.random() * 4) == 3) {
+                clearInterval(element[1]);
+                element[0].className = "explosion";
+            }
+        }
+    }
 }

scripts/projectile.js

@@ -1 +1,2 @@
 /* logic for bombs */
+