The demand is like this. The navigation of many PC web pages is fixed, such as the homepage of Google. Now if we want to transfer this fixed navigation to the mobile web, it is natural to think of position: fixed; bottom: 0, android It runs normally under iPhone Safari, but there will be a problem under iPhone Safari. When the scroll bar scrolls, the navigation bar will appear at the top of the screen, a dark piece, which is very uncoordinated. Many people recommend frameworks such as iscroll and jquery mobile, but sometimes the results are not satisfactory or you have to read the source code of the framework for secondary development, which will take a long time. After a period of research, I found a solution, which is relatively simple, but the effect is still not as good as pc web.