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+# Monster example slug
+
+This article describes a very simple web page that we'll use to
+illustrate some features of the Memory tool.
+
+You can try the site at
+<https://mdn.github.io/performance-scenarios/js-allocs/alloc.html>.
+Heres the code:
+
+```js
+var MONSTER_COUNT = 5000;
+var MIN_NAME_LENGTH = 2;
+var MAX_NAME_LENGTH = 48;
+
+function Monster() {
+
+  function randomInt(min, max) {
+      return Math.floor(Math.random() * (max - min + 1)) + min;
+    }
+
+  function randomName() {
+    var chars = "abcdefghijklmnopqrstuvwxyz";
+    var nameLength = randomInt(MIN_NAME_LENGTH, MAX_NAME_LENGTH);
+    var name = "";
+    for (var j = 0; j &lt; nameLength; j++) {
+      name += chars[randomInt(0, chars.length-1)];
+    }
+    return name;
+  }
+
+  this.name = randomName();
+  this.eyeCount = randomInt(0, 25);
+  this.tentacleCount = randomInt(0, 250);
+}
+
+function makeMonsters() {
+  var monsters = {
+    "friendly": [],
+    "fierce": [],
+    "undecided": []
+  };
+
+  for (var i = 0; i &lt; MONSTER_COUNT; i++) {
+    monsters.friendly.push(new Monster());
+  }
+
+  for (var i = 0; i &lt; MONSTER_COUNT; i++) {
+    monsters.fierce.push(new Monster());
+  }
+
+  for (var i = 0; i &lt; MONSTER_COUNT; i++) {
+    monsters.undecided.push(new Monster());
+  }
+
+  console.log(monsters);
+}
+
+var makeMonstersButton = document.getElementById("make-monsters");
+makeMonstersButton.addEventListener("click", makeMonsters);
+```
+
+The page contains a button: when you push the button, the code creates
+some monsters. Specifically:
+
+-   the code creates an object with three properties, each an array:
+    -   one for fierce monsters
+    -   one for friendly monsters
+    -   one for monsters who haven't decided yet.
+-   for each array, the code creates and appends 5000
+    randomly-initialized monsters. Each monster has:
+    -   a string, for the monster's name
+    -   a number representing the number of eyes it has
+    -   a number representing the number of tentacles it has.
+
+So the structure of the memory allocated on the JavaScript heap is an
+object containing three arrays, each containing 5000 objects (monsters),
+each object containing a string and two integers:
+
+[![](../img/monsters.svg)]