C:\Users\Brett\Desktop\testIframeNew1.js

(function () {

function _addClick(browser, textboxID) {
	return function (e) {
		try {
			netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect");
			function loaded () {
				try {
					netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect");
					var urlbarURL = browser.getUserData('urlbarURL');
					var url = urlbarURL || browser.contentDocument.defaultView.location.href;
					if (urlbarURL) {
						browser.setUserData('urlbarURL', null, null);
					}
					
					if (browser.getUserData('backNow')) { // This load was a result of a back event, so don't increment as we normally do
						browser.setUserData('backNow', false, null);
						return;
					}
					if (browser.getUserData('forwardNow')) { // This load was a result of a forward event, so don't alter the array as we normally do
						browser.setUserData('forwardNow', false, null);
						return;
					}
					var history = browser.getUserData('history');
					if (history == null) {
						history = [browser.src];
						browser.setUserData('history', history, null);
						browser.setUserData('historyPointer', 0, null);
					}
					var historyPointer = browser.getUserData('historyPointer');
					history.splice(historyPointer+1, history.length, url);
					document.getElementById(textboxID).value = url;

					var newPointer = historyPointer+1;
					browser.setUserData('historyPointer', newPointer, null);
					browser.setUserData('history', history, null);
				}
				catch(err) {
					alert(err);
				}
			}
			browser.addEventListener('load', loaded, false);
			browser.setUserData('hasListener', true, null);
		}
		catch(err) {
			alert(err);
		}
	};
}

function goURL (iframeID, textboxID) {
	try {
		netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect");
		var browser = document.getElementById(iframeID);
		var textbox = document.getElementById(textboxID);
		if (!browser.getUserData('hasListener')) {
			_addClick(browser, textboxID)();
		}
		browser.setUserData('urlbarURL', textbox.value, null);
		browser.contentDocument.defaultView.location.href = textbox.value;
	}
	catch(e) {
		alert(e);
	}
}

function back (iframeID, textboxID) {
	try {
		netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect");
		var browser = document.getElementById(iframeID);
		var history = browser.getUserData('history');
		if (!history) {
			return;
		}
		var historyPointer = browser.getUserData('historyPointer');
		if (historyPointer >= 1) {
			var newPointer = historyPointer-1;
			browser.setUserData('historyPointer', newPointer, null);
			browser.setUserData('backNow', true, null);
			browser.contentDocument.defaultView.location.href = history[newPointer];
			document.getElementById(textboxID).value = history[newPointer];
		}
	}
	catch(e) {
		alert(e);
	}
}

function forward (iframeID, textboxID) {
	netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect");
	var browser = document.getElementById(iframeID);
	var history = browser.getUserData('history');
	if (!history) {
		return;
	}
	var historyPointer = browser.getUserData('historyPointer');

	if (historyPointer < history.length-1) {
		var newPointer = historyPointer+1;
		browser.setUserData('historyPointer', newPointer, null);
		browser.setUserData('forwardNow', true, null);
		browser.contentDocument.defaultView.location.href = history[newPointer];
		document.getElementById(textboxID).value = history[newPointer];
	}
}

window.addEventListener('load', function () {
	var frameBrowsers = document.getElementsByClassName('frameBrowser');
	for (var i=0, fbl=frameBrowsers.length; i < fbl; i++) {
		var browser = frameBrowsers[i];
		try {
			netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect");
			var number = browser.id.replace(/^iframeBrowser/, ''); // (i+1) would works, but only for sequential entries starting from 1, so to be safe, we depend on the ID which contains the number
			_addClick(browser, 'urlBar'+number)();
			//browser.contentDocument.addEventListener('click', _addClick(browser, 'urlBar'+number, true), true); // Shouldn't it be true????
			document.getElementById('urlBar'+number).value = browser.src;
		}
		catch(e) {
			alert(e);
		}
	}
}, false);


var JSBrowser = {};
JSBrowser.goURL = goURL;
JSBrowser.back = back;
JSBrowser.forward = forward;
JSBrowser._addClick = _addClick;

this.JSBrowser = JSBrowser;

}());

JavaScriptBrowsers.xhtml

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Frameset//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-frameset.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
	<title>Independent JavaScript Browsers</title>
	<script type="text/javascript" src="testIframeNew1.js"></script>
	<link rel="stylesheet" type="text/css" href="testIframeNew1.css" />
</head>
<body>

<div class="set">
	<div><a id="back1" href="javascript:void(0);" onclick="JSBrowser.back('iframeBrowser1', 'urlBar1');">&lt;</a> &#160; <a href="javascript:void(0);" id="forward1" onclick="JSBrowser.forward('iframeBrowser1', 'urlBar1');">&gt;</a> &#160; <input id="urlBar1" type="text" size="50" /> <input type="button" onclick="JSBrowser.goURL('iframeBrowser1', 'urlBar1');" value="Go!" /></div>
	<iframe id="iframeBrowser1" class="frameBrowser" src="test3Iframe.html"></iframe>
</div>

<div class="set">
	<div><a id="back2" href="javascript:void(0);" onclick="JSBrowser.back('iframeBrowser2', 'urlBar2');">&lt;</a> &#160; <a href="javascript:void(0);" id="forward2" onclick="JSBrowser.forward('iframeBrowser2', 'urlBar2');">&gt;</a> &#160; <input id="urlBar2" type="text" size="50" /> <input type="button" onclick="JSBrowser.goURL('iframeBrowser2', 'urlBar2');" value="Go!" /></div>
	<iframe id="iframeBrowser2" class="frameBrowser" src="test2Iframe.html"></iframe>
</div>

</body>
</html>

test2Iframe.html

<a href="http://www.yahoo.com">Yahoo</a>

test3Iframe.html

<a href="http://www.google.com">Google</a>

testIframeNew1.css

.set {float:left;width:50%}
.frameBrowser {width:450px;height:500px;}