Let’s take a look at the content introduced by the nodejs server

As you can see, we have introduced the jQuery plug-in, and then we will run the server

node server.js

It’s strange that I made a mistake. When I debugged on windows, I had no problem,

Later I learned that the Linux server is case sensitive,

Our dependent folder node_ The jQuery under modules is like this

But when we quote, the Q letter of jQuery uses the uppercase Q, just change it to lowercase