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<!DOCTYPE html>
<html>
<body>
​
<h1>JavaScript Getter 和 Setter</h1>
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<p>创建完美的计数器：</p>
​
<p id="demo"></p>
​
<script>
// 定义对象
var obj = {counter : 0};
​
// 定义 Setter 和 Getter
Object.defineProperty(obj, "reset", {
????get : function () {this.counter = 0;}
});
Object.defineProperty(obj, "increment", {
????get : function () {this.counter++;}
});
Object.defineProperty(obj, "decrement", {
????get : function () {this.counter--;}
});
Object.defineProperty(obj, "add", {
????set : function (value) {this.counter += value;}
});
Object.defineProperty(obj, "subtract", {
????set : function (value) {this.counter -= value;}
});
​
// 操作计数器：
obj.reset;
obj.add = 5;
obj.subtract = 1;
obj.increment;
obj.decrement;
document.getElementById("demo").innerHTML = obj.counter;
</script>
​
</body>
</html>
​