It was probably during the few months when I was preparing for the postgraduate entrance exam that I never even opened my own laptop, so during that time, whenever I wanted to go online, I used my roommate's computer. They all used the 360 Browser, and as a result, I developed the habit of using it too. However, recently, I just couldn't stand that lousy browser anymore, so I switched back to my beloved Firefox (FF). When I first started using it again, I visited my own blog and noticed some issues. Specifically, on the homepage, there was a strange character appearing in the summary of each article (some articles had it, while others didn’t; I’ll explain the reason below).
A little thought would lead you to guess that the issue is caused by the `substring` function, which exists in C++ (`substr`), PHP, and Java. Imagine if you use `substring($string, 0, 150)`, and the 150th and 151st characters happen to form a single Chinese character together, then you have a problem.