如何检查 JavaScript 中某个对象是否是某个类的实例?

javascriptweb developmentobject oriented programming更新于 2025/9/2 8:44:17

以下是检查 JavaScript 中某个对象是否是某个类的实例的代码 −

示例

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>Document</title>
<style>
   body {
      font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
   }
   .result {
      font-size: 20px;
      font-weight: 500;
      color: blueviolet;
   }
</style>
</head>
<body>
<h1>Check if an object is an instance of a Class</h1>
<div class="result"></div>
<button class="btn">点击此处</button>
<h3>Click on the above button to check if student1 object is an instance of Student</h3>
<script>
   let resEle = document.querySelector(".result");
   function Student(name, age, standard) {
      this.name = name;
      this.age = age;
      this.standard = standard;
   }
   let student1 = new Student("Rohan", 18, 12);
   document.querySelector(".Btn").addEventListener("click", () => {
      if (student1 instanceof Student) {
         resEle.innerHTML = "student1 is instance of Student";
      } else {
         resEle.innerHTML = "student1 is not an instance of Student";
      }
   });
</script>
</body>
</html>