audio alert notification when web page content changes

My firm receives "advertised orders" after logging in to our client's website.? After logging in and going to the web page with advertised orders, we see any advertised orders that exist.? Given the competitive nature of my business, other firms snap up those advertised orders extremely quickly.? As a result, we have created a simple tool to refresh the screen every 20 seconds so that we can see new advertised orders within 20 seconds of their entry into the system.? The text on the screen consistently indicates "no advertised orders."? When an advertised order appears, we attempt to quickly click on the link to accept that advertised order.? Very frequently, other firms are quicker.? Because my staff is working on other adminstrative projects and not staring at the screen to catch advertised orders at every moment, and because we are monitoring 7 or 8 accounts that each have advertised orders from the same client, we would like to improve our system so that we receive an instant beep when the content on the page changes.? The window refreshes every 20 seconds so we cannot have a beep every 20 seconds.? We just need a beep when the "no advertised orders" content changes.? Because of the nature of the website, we monitor 3 accounts on? each computer? (1 account with Internet Explorer, 1 account with Google Chrome, and 1 account with Mozilla Firefox).? We do the same on other computers.? We can't monitor 2 accounts on the same computer with a single web browser, so we use 3 different web browsers.? This is OK, as long as your application works with all three web browsers as we run them simultaneously on a computer.? Further questions prior to bidding would be acceptable.? Thank you