1. Website structure When the website is revised, try not to change the website structure, and the navigation part of the url is consistent with the original effect, so that the search engine can recapture the url. Although the code part will be different, at least there will be no dead links. This is also a kind of friendliness to Baidu search engine.

2. When the website is revised, the original website design style will always be affected. Some front-ends will not delete those invalid codes, but only add some new functional codes, which will lead to some code redundancy, possibly some invalid js errors, and eventually lead to the degradation of the website.

3. Database Slimming After the revision of the website of Shanghai Enterprise, many of the original databases are invalid data. Deleting those invalid data can improve the loading speed of the website.