用 JavaScript 中的 call() 和 apply() 调用函数

以下是用 JavaScript 中的 call() 和 apply() 调用函数的代码 −

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: 18px;
      font-weight: 500;
      color: blueviolet;
   }
</style>
</head>
<body>
<h1>Invoking functions with call() and apply()</h1>
<div class="result"></div>
<br />
<button class="Btn">Click Here</button>
<h3>Click on the above buttons to invoke functions with call() and apply()
method</h3>
<script>
   let resEle = document.querySelector(".result");
   let BtnEle = document.querySelector(".Btn");
   function addNum(num1, num2, num3, num4) {
      return num1 + num2 + num3 + num4;
   }
   function multiplyNum(num1, num2, num3, num4) {
      return num1 * num2 * num3 * num4;
   }
   let arr = [22, 33, 44, 55];
   BtnEle.addEventListener("click", () => {
      resEle.innerHTML = "Sum of the numbers = " + addNum.call(this, 22, 33, 44, 55) + "<br>";
      resEle.innerHTML +="Multiplication of the array elements = " +multiplyNum.apply(this, arr) +"<br>";
   });
</script>
</body>
</html>