Why are two pages displayed?

Question

JavaScript

I don’t understand how this can be, in the console, when the page is opened, two files
index.html and signup.php are displayed at once, although only index.html should be loaded

Answer 1

Because there is an error on the page, which in some cases loads the second file.
You don't need to look for dependency.
You need to put the programmer to look at the contents of index.html and find the error.