Script for retaining users on a website

The script for retaining users on the site and increasing conversion was written in JavaScript, HTML, and CSS. The essence of the script is that when a user tries to leave the site, they are asked a question in a pop-up window — did they find what they wanted? If they did, they are offered to be told about promotions on the site; if not, they are simply offered to have an operator call them back. In both cases the user enters a phone number and an operator should call them back within 15 seconds. If the operator did not manage to, the user can report this by clicking a special button "No, you didn't make it!"