Prevent Web Terminal Close

As Green Screens 5250 Terminal is web based and runs in browser tabs, it is highly likely that user might to accidentally close browser window and thus terminal session also.

There are few approaches to prevent this...

  • single user script through TamperMonkey browser extension
  • through Web Admin console global script
  • through latest Green Screens browser extension

If you have Green Screens Terminal version older than 3.8.0, first two options are the only options. Below is a simple script that will activate browser close detection and show popup window asking for confirmation.

If you want to set this feature for all users, simply add script in web admin console customization box.

NOTE: Don't forget to wrap code inside script tag!

// ==UserScript==
// @name           WebTerminalScripts
// @namespace      http://www.greenscreens.io
// @description    Sample Hello world script
// @copyright      2017. Green Screens Ltd.
// @version        1.0
// @license        BSD
// @author         Green Screens Ltd.
// @homepage       http://www.greenscreens.io
// @icon           http://www.greenscreens.io/assets/images/logo.png
// @updateURL
// @run-at         document-end
// @match          http*://*/lite*
// @grant          none
// @noframes
// ==/UserScript==

(function() {
    'use strict';
    
    window.onbeforeunload = function(event) {
    	if (Tn5250 && Tn5250.Browser) {
            return "Your work will be lost.";	
    	}
    };
 
})();