Automating opening a local file in a browser?

Question

Automation

There is a task: to automate uploading a file from a local HDD to a web interface through a browser, through the Open File Dialog. No extensions and tampermonkey can do this, because. browsers in their normal form stop such things. You also need scripted automation of the "user" actions (click on the link, etc.).
I suppose some custom build of firefox/chromium would help me. Are there any ready-made solutions and thoughts on this?

Answer 1

Try something from: Phantomjs, Selenium Webdriver + Chromium/Firefox, CEF, HumanEmulator.

Answer 2

Test script code on Clickerman:

lclick(100,200) // комментарии: click on link
wait(1) // wait 1 sec
keystring("filename.htm") // input a file mask or name
keypress(#enter) // confirm your input name
lclick(150,250) // click on file to select
halt // end

It remains to substitute only the necessary coordinates of clicks to configure the script and, if necessary, set the necessary delays (depending on your hardware).