So the task is to call a javascript script on a php request?

Question

PHP

There is a php parser that checks info. As soon as the infa has changed, php must somehow convey this to the plugin in chrome on a java script, which will instantly react and click on the button with the desired id.
The bottom line is to go to the desired site and click the buy button. As soon as php sees that the price has dropped low.
Here's how to implement it?

Answer 1

websockets, server push

Answer 2

Phantomjs, plugin is not needed, you can "press buttons" from the server.