How to solve javascript failure after splitting files

With the development of the Internet, JavaScript has become an indispensable part of web development. However, when we use split-file development, we sometimes encounter a strange problem: JavaScript fails in different files. So why does this happen? How can we solve this problem?

First, let us explain what "part-file development" means. In web development, we usually put CSS, JavaScript, HTML and other content in different files for development. This can make our code clearer and easier to understand, and can be easily maintained. However, when we use JavaScript in different files, code failure may occur.

The root cause of this problem is the execution order of JavaScript. In HTML, code is executed in the order in which it is written. However, in file-by-file development, since there may be dependencies between different files, the execution order of the files cannot be guaranteed. This leads to the situation when we define a function and other operations in one file, but the function cannot be found in another file.

So, how can we solve this problem? Below we will provide some general solutions:

1. Use the