$ipspReady.js

    function $ipspReady(success, failure) {
        var win = window, doc = document, name = '$ipsp', tag = '$ipspScriptTag', head, script, 
            url = 'https://api.fondy.eu/static_common/v1/checkout/ipsp.js';
        if (name in win) return success(win[name]);
        if (tag in win) {
            script = win[tag];
        } else {
            head = doc.querySelector('head');
            script = doc.createElement('script');
            script.async = true;
            script.src = url + '?_=' + new Date().getTime();
            head.appendChild(script);
            win[tag] = script;
        }
        script.addEventListener('load', function () {
            success(win[name])
        });
        script.addEventListener('error', failure);
    }

$ipspReady(function ($ipsp) {
    $ipsp.get('checkout').config({
        'wrapper': '#container',
        'styles': {
            'body': {'overflow': 'hidden'},
            '.page-section-shopinfo': {display: 'none'},
            '.page-section-footer': {display: 'none'}
        }
    }).scope(function () {
        this.loadUrl('checkout_url');
    });
});