How do I gracefully interrupt loading of a certain URL in Cordova's InAppBrowser and open it in the system browser?

So I ended up with the following code:

openWithSystemBrowser = function(url) {
    window.open(url, "_system");
    location.href = "index.html";
};

shareOnWhatsapp = function(url) {
    openWithSystemBrowser(url);
};

/**
 * Handles URL changes in in-app browser, e.g. to handle logouts or
 * unsuccessful logins
 */
urlChanged = function(event) {
    if(event.url.startsWith("http://whatsapp://")) {
        shareOnWhatsapp(event.url.substr("http://".length));
        return;
    }
    if(event.url.startsWith("whatsapp://")) {
        shareOnWhatsapp(event.url);
        return;
    }
};

This is of course slightly lame as you're always brought back to index.html, but for my purposes it was enough. Interested to see if anyone's found a more elegant solution.

It also solved the 2-3 second delay before opening the system browser, but I don't have any clue why, frankly.

I found an approach with a better user experience: When loading an external URL in the system browser, I close the InAppBrowser and reopen it with the last internal URL.

var appUrl = 'https://www.my-website.com';

var app = {

    currentUrl: appUrl,

    initialize: function() {
        document.addEventListener('deviceready', this.onDeviceReady.bind(this), false);
    },

    onDeviceReady: function() {
        app.openBrowser();
    },

    openBrowser: function() {
        var target = '_blank';
        var options = [
            "location=no",
            "clearcache=no",
            "clearsessioncache=no",
            "footer=no",
            "hardwareback=no",
            "hideurlbar=yes",
            "zoom=no",
            "hidenavigationbuttons=no",
            "toolbar=yes",
            "hidespinner=yes",
            "toolbarcolor=#000000",
            "toolbartranslucent=no",
            "navigationbuttoncolor=#ffffff",
            "closebuttoncolor=#000000",
            "closebuttoncaption="
        ];

        browser = cordova.InAppBrowser.open(app.currentUrl, target, options.join());

        // reopen the browser if it was closed via "Done" button
        browser.addEventListener('exit', function(){ app.openBrowser(); } );

        // open external urls in system browser window
        browser.addEventListener('loadstart', function(event){ app.handleUrl(event.url, browser); });
    },

    handleUrl: function(url, browser) {
        var extension = url.split('.').pop();

        // load internal urls that are not pdf files in the app browser
        if (extension != 'pdf' && url.startsWith(appUrl)) {
            app.currentUrl = url;
            return;
        }

        // open website in system browser window
        var ref = cordova.InAppBrowser.open(url, '_system', 'location=no');

        // since the inapp browser is loading the website too, close it and open it again with the last internal url visited
        browser.close();
        app.openBrowser();

        return;
    }
};

app.initialize();