一、新增语义化标签

        1、块元素

                <header></header>

                <section></section>

                <nav></nav>

                <main></main>

                <footer></footer>

                <aside></aside>

                <article></article>

                <figure>
                        <figcaption>独立流内容标题</figcaption>
                        独立流内容（图表、代码、表格等）
                </figure>

                <details>
                        <summary>概要</summary>
                        内容
                 </details>

        2、内联元素

                <progress value="进度值" min="最小值"max="最大值">
                        你的浏览器不支持
                </progress>

                <meter value="值" min="" max="" low="" high="">your</meter>

                <time datetime="年月日"><time>

                <mark>标记</mark>