xxxxxxxxxx<html><head> <meta charset="utf-8"> <title>W3Cschool(w3cschool.cn)</title> </head><body><h1 style="text-align:center">这是标题 1</h1><h2 style="text-align:left">这是标题 2</h2><h3 style="text-align:right">这是标题 3</h3><h4 style="text-align:justify">这是标题 4</h4></body></html>