html运行实例（eg_js_datatypes_undefined

代码示例：（标识：eg_js_datatypes_undefined_3）

<!DOCTYPE html>
<html>
<body>

<h2>JavaScript 数据类型</h2>

<p>任何变量均可通过设置值为 undefined 进行清空。其类型也将是 undefined。</p>

<p id="demo"></p>

<script>
var person = {firstName:"Bill", lastName:"Gates", age:62, eyeColor:"blue"};
person = undefined;
document.getElementById("demo").innerHTML = person;
</script>

</body>
</html>