显示所有变量的类型
显示所有变量的类型

<!DOCTYPE html>
<html>
<body>
 
<h2>JavaScript typeof 运算符</h2>
 
<p>typeof 运算符返回变量、对象、函数或表达式的类型。</p>
 
<p id="demo"></p>
 
<script>
document.getElementById("demo").innerHTML = 
  typeof "john" + "<br>" +
  typeof 3.14 + "<br>" +
  typeof NaN + "<br>" +
  typeof false + "<br>" +
  typeof [1,2,3,4] + "<br>" +
  typeof {name:'john', age:34} + "<br>" +
  typeof new Date() + "<br>" +
  typeof function () {} + "<br>" +
  typeof myCar + "<br>" +
  typeof null;
</script>
 
</body>
</html>