How to make such a file uploader to the site?

Question

css

Good afternoon.
There was a need to make convenient loading of HTML pages on the site. The idea is this: The user in the browser specifies index.html, the browser reads this file, pulls all links to images, css and js from there and adds links to all these files to the hidden form fields. Accordingly, when submitting the form, the page goes to the back along with all the related files, and they are already being processed there, etc.
The question is this: As I understand it, this cannot be done using JS, since the browser does not allow working with the file system. What are the options to make a similar bootloader? It is desirable without the participation of ActiveX and Flash, because bad manners. Or maybe some other way to organize such a thing? In general, the opinion of experienced comrades is needed.
Thanks in advance to all who answer.

Answer 1

php.net/file%20get%20contents
+
simplehtmldom.sourceforge.net
In the form, only the address, html is taken on the server, parsed, images are retrieved and loaded.