HTML，CSS 和 JavaScript 创建一个简单的 网页代码兼容性测试工具

下面是一个简单的HTML，CSS和JavaScript代码，可以用来创建一个网页浏览器兼容性测试工具：

<!-- HTML Code - Main Content -->
<div>
    <h1>Compatibility Test</h1>
    <p>This page tests your browser's compatibility with HTML, CSS and JavaScript.</p>
 
    <div>
        <h2>HTML</h2>
        <p>This paragraph contains basic HTML code.</p>
    </div>
 
    <div>
        <h2>CSS</h2>
        <div style="background-color: green;">
            <p>This paragraph contains a CSS element.</p>
        </div>
    </div>
 
    <div>
        <h2>JavaScript</h2>
        <button onclick="alert('This button runs a JavaScript function.')">Click Me</button>
    </div>
</div>

/* CSS Code */
body {
    font-family: sans-serif;
}

h1 {
    font-size: 32px;
    color: #444;
}

h2 {
    font-size: 24px;
    color: #555;
}

p {
    font-size: 16px;
    color: #666;
}

// JavaScript Code
function alertMessage() {
    alert("This is a test message!");
}