js meta 动态赋值

<meta name="description" content="这是一个示例描述">

document.title = "新的页面标题";

function updateMeta(name, content) {
    let element = document.querySelector(`meta[name="${name}"]`);
    if (!element) {
        element = document.createElement('meta');
        element.name = name;
        document.head.appendChild(element);
    }
    element.content = content;
}

// 使用示例
updateMeta('description', '这是新的页面描述');
updateMeta('keywords', 'JavaScript, 动态, meta');

function updateViewport(width, initialScale) {
    let viewport = document.querySelector('meta[name="viewport"]');
    if (!viewport) {
        viewport = document.createElement('meta');
        viewport.name = 'viewport';
        document.head.appendChild(viewport);
    }
    viewport.content = `width=${width}, initial-scale=${initialScale}`;
}

// 使用示例
updateViewport('device-width', '1.0');

window.addEventListener('load', function() {
    // 页面加载完成后执行的代码
    updateMeta('description', '页面已加载');
});