JavaScript Let

2015 年引入的 JavaScript Let 關鍵字允許我們定義塊範圍變數。

以下是使用 JavaScript 中的 Let 關鍵字宣告變數的程式碼 −

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;
   }
   .sample{
      font-size: 18px;
      font-weight: 500;
      color: red;
   }
</style>
</head>
<body>
<h1>JavaScript Let</h1>
<div class="sample"></div>
<div style="font-weight: bold; color: black;" class="result"></div>
<button class="Btn">CLICK HERE</button>
<h3>
Click on the above button to access the varible
</h3>
<script>
   let sampleEle = document.querySelector(".sample");
   document.querySelector(".Btn").addEventListener("click", () => {
      {
         let a = 22;
         sampleEle.innerHTML ="Accessing variable a inside block = " + a + "<br>";
      }
      try {
         sampleEle.innerHTML = "Accessing variable a outside block = " + a;
      } catch (err) {
         sampleEle.innerHTML +="Accessig variable a outside the block = " + err;
      }
   });
</script>
</body>
</html>