Learn-JavaScript/8. Variable Scope.html at main · Sandeep6135/Learn-JavaScript · GitHub

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<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <title>JS Scope Visualizer</title>
    <style>
        body {
            font-family: system-ui;
            padding: 2rem;
            color: #333;
        }

        .container {
            max-width: 400px;
            border: 2px solid #ddd;
            padding: 20px;
            border-radius: 12px;
        }

        button {
            background: #f7df1e;
            border: 1px solid #333;
            padding: 10px 15px;
            border-radius: 4px;
            font-weight: bold;
            cursor: pointer;
        }

        .scope-label {
            font-size: 0.8rem;
            color: #666;
            text-transform: uppercase;
            margin-bottom: 4px;
        }

        .result-box {
            margin-top: 20px;
            padding: 15px;
            background: #f0f0f0;
            border-left: 4px solid #f7df1e;
        }

        .error {
            color: #d93025;
            font-weight: bold;
        }
    </style>
</head>

<body>

    <div class="container">
        <h2>JS Scope Demo</h2>
        <p>Global Variable: <code>"I am global"</code></p>
        <button onclick="runScopeTest()">Run Scope Test</button>

        <div id="output" class="result-box">
            Click the button to see scope in action.
        </div>
    </div>

    <script>
        // GLOBAL SCOPE: Accessible from everywhere
        let globalVar = "I am global";

        function runScopeTest() {
            // LOCAL (FUNCTION) SCOPE: Only accessible inside these curly braces
            let localVar = "I am local";

            let output = document.getElementById("output");

            output.innerHTML = `
                <div class="scope-label">Inside the Function:</div>
                ✅ Global: ${globalVar}<br>
                ✅ Local: ${localVar}<br>
                <hr>
                <div class="scope-label">Outside the Function:</div>
                ✅ Global: ${globalVar}<br>
                ❌ Local: <span class="error">ReferenceError</span>
            `;
        }
    </script>
</body>

</html>