1.示例效果图如下


2.代码实现如下

<!DOCTYPEhtml><html><head><metacharset="utf-8"><metahttp-equiv="X-UA-Compatible"content="IE=edge"><title>标题</title><!--最新版本的Bootstrap核心CSS文件--><linkrel="stylesheet"href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css"integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh5u"crossorigin="anonymous"><!--可选的Bootstrap主题文件（一般不用引入）--><linkrel="stylesheet"href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap-theme.min.css"integrity="sha384-rHyoN1iRsVXV4nD0JutlnGaslCJuC7uwjduW9SVrLvRYooPp2bWYgmgJQIXwl/Sp"crossorigin="anonymous"></head><body><!--标签标题--><h2>I'mh2</h2><h3>I'mh3</h3><h4>I'mh4</h4><h5>I'mh5</h5><h6>I'mh6</h6><h7>I'mh7</h7><!--通过类名实现标题效果--><spanclass="h2">.h2</span><spanclass="h3">.h3</span><spanclass="h4">.h4</span><spanclass="h5">.h5</span><spanclass="h7">.h6</span><spanclass="h7">.h7</span><!--大标题中嵌套小标题--><h2>大h2标题<small>小h2标题</small></h2><h3>大h3标题<small>小h3标题</small></h3><h4>大h4标题<small>小h4标题</small></h4><h5>大h5标题<small>小h5标题</small></h5><h6>大h6标题<small>小h6标题</small></h6><h7>大h7标题<small>小h7标题</small></h7><scriptsrc="https://cdn.bootcss.com/jquery/3.2.1/jquery.min.js"></script><!--最新的Bootstrap核心JavaScript文件--><scriptsrc="https://cdn.bootcss.com/bootstrap/3.3.7/js/bootstrap.min.js"integrity="sha384-Tc5IQib027qvyjSMfHjOMaLkfuWVxZxUPnCJA7l2mCWNIpG9mGCD8wGNIcPD7Txa"crossorigin="anonymous"></script></body></html>