We tend to go directly to the main text and forget about headers and footers , where more than one grave error lies in hiding .
我们往往直接专注于主体正文，而忽略了标题和脚注，那里可能藏有不止一个严重的错误。
Most html 4 pages include a variety of common structures , such as headers , footers and columns and today , it is fairly common to mark them up using div elements , giving each a descriptive id or class .
