现场演示：我的 HTML 文档

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>Check If Object is an Array in JavaScript</title>
</head>
<body>
    <script>
        // Creating some variables
        var v1 = {name: "John", age: 18};   
        var v2 = ["red", "green", "blue", "yellow"];
        var v3 = [1, 2, 3, 4, 5];
        var v4 = null;
        
        // Testing the variables data type
        document.write(typeof(v1) + "<br>"); // Prints: "object"
        document.write(typeof(v2) + "<br>"); // Prints: "object"
        document.write(typeof(v3) + "<br>"); // Prints: "object"
        document.write(typeof(v3) + "<hr>"); // Prints: "object"
        
        // Testing if the variable is an array
        document.write(Array.isArray(v1) + "<br>");  // Prints: false
        document.write(Array.isArray(v2) + "<br>");  // Prints: true
        document.write(Array.isArray(v3) + "<br>");  // Prints: true
        document.write(Array.isArray(v4));  // Prints: false
    </script>
</body>
</html>