<!DOCTYPE html>
<html>
<body>
<h2>JavaScript 数据类型</h2>
<p>空的字符串变量既有值也有类型。</p>
<p id="demo"></p>
<script>
var car = "";
document.getElementById("demo").innerHTML =
"其值是：" +
car + "<br>" +
"类型是：" + typeof car;
</script>
</body>
</html>