(function() { var enemiesDataStr = document.getElementById("enemies").innerHTML; var enemiesDataObj = JSON.parse(enemiesDataStr); function Enemy(type) { var data = enemiesDataObj[type]; this.hp = data.hp; this.attack = data.attack; } Enemy.prototype.damage = function(amount) { this.hp -= amount; } var myEnemy = new Enemy("wolf"); document.write("HP now at " + myEnemy.hp + "<br>"); myEnemy.damage(5); document.write("HP now at " + myEnemy.hp + "<br>"); }());
<script id="enemies" type="json"> { "bat": { "hp": 10, "attack": 1 }, "wolf": { "hp": 50, "attack": 4 }, "dragon": { "hp": 1000, "attack": 90 } } </script>