I want an E&D project where my developer can intercept browser exit session from someone. I want to give my button (special purpose) to various eCommerce Shop owners when their visitors are leaving or moving away from their product catalog (on their website). They could be having wordpress, php, shopify, magento, bigcommerce -- different kind of websites so ideally I am looking for a solution where you can intercept back button or exit from the website (moving to other URL) or something..
If you can provide solution for any web technologies, my budget is higher. For one technology, it would be lower for R&D.