< html xmlns = "http://www.phpernote.com/php-function/1022.html" > |
< head > |
< meta http-equiv = "Content-Type" content = "text/html; charset=utf-8" /> |
< title >html文件的上标字与下标字</ title > |
</ head > |
< body > |
< p >数学公式 : (x+y)< sup >2</ sup > = x< sup >2</ sup > + 2xy + y< sup >2</ sup ></ p > |
< p >化学方程式 : H< sub >2</ sub >O = 2H + O</ p > |
</ body > |
</ html > |