分两步
- 使用相应的id名标注跳转目标的位置，（找目标）
- 使用<a herf="id名">链接文本</a> 创建链接文本（被点击的）（拉关系）
When nothing seems to help, I go look at a stonecutter hammering away at his rock, perhaps a hundred times without as much as a crack showing in it. Yet at the hundred and first blow it will split in two, and I know it was not that blow that did it, but all that had gone before. -- Jacob Riis