How to combine multiple HTML files into one, like Sass, using css using @import?

In Sass, we can combine several particles into one css output, for example

@import "scss/header";
@import "scss/footer";
@import "scss/navigation";
@import "scss/sidebar";

at

final.scss >final.css

Is there any method for this with raw .HTMLfiles (not .php or .asp), for example

@import "header.html";
@import "scss/footer.html";
@import "scss/navigation.html";
@import "scss/sidebar.html";

at index.html

The above is just an example explaining what I ask

I know I can do this using php, but I want to know if I can only use .html files. I just want to combine files on my PC, not on the server.