<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta http-equiv="content-Type" charset="UTF-8"> <meta http-equiv="x-ua-compatible" content="IE=edge"> <meta name="viewport" content="width=device-width, initial-scale=1"> <title>Title</title> </head> <body> <!--语义化标签--> <!--u标签：underline下划线--> <u>小马哥</u> <!--b标签：粗体文本--> <b>小马哥</b> <!--em：斜体--> <em>小马哥</em> <!--上角标--> 2<sup>3</sup> <!--下角标--> 8<sub>4</sub> </body> </html>