What if the regex or operator "|" in a regular expression uses the prone feature Bug

This article mainly shows you the "regular expression regex or operator" | "how to use the easy-to-appear function Bug", the content is easy to understand, clear, hope to help you solve your doubts, the following let Xiaobian lead you to study and learn "regular expression regex or operator" | "how to use easy-to-appear function Bug" this article.

Regular expression (regex) misuse leads to functional loopholes, we continue to comb, regular expression misuse, leading to functional design loopholes (bug), do web, need to master a lot of knowledge, website development work, in China for more than 10 years, many developers, are through: training (self-study)-> imitation-> do the project, such a process. Many of them become web development engineers after revision and modification. The entry-level of this profession is low and it is easy to get started. But it's not easy to be a master. Need to learn, master dozens of knowledge. For beginners, most of the time, because of the lack of systematic learning, theoretical support. Lead to the promotion of some willing but not enough! Therefore, these more or less functional design loopholes are very common!

Well, some of them are beside the point, and this kind of loophole often appears when doing code walk check. Let's take a look at the following code: