Javascript prototype inheritance

gistfile1.js

var app = {};

Function.prototype.inherits = function (base) {
    var isFunction = base.constructor == Function;
    this.prototype = isFunction ? new base : base;
    this.prototype.constructor = this;
    return this;
};

(function (app) {

    var forEach = function (collection, fn) {
        var count = collection.length;
        if (count) {
            var i = 0;
            for (; i < count; i++) {
                if (fn.call(collection[i], collection[i]) === false) {
                    break;
                }
            }
        }
    };

    var forEachWith = function (collection, context, fn) {
        forEach(collection, function () {
            fn.call(context, this);
        });
    };

    app.utils = {
        forEach: forEach,
        forEachWith: forEachWith
    }

}(app));

(function (app) {

    var Modal = function (title) {
        this.title = title;
    };

    Modal.prototype.show = function () {
        this.el.style.display = 'block';
    };

    Modal.prototype.hide = function () {
        this.el.style.display = 'none';
    };

    Modal.prototype.init = function () {
        this.el = document.createElement('div');
        this.hide();

        var footer = document.createElement('div');
        footer.className = 'footer';
        this.el.appendChild(footer);

        document.body.appendChild(this.el);

        return this;
    };

    Modal.prototype.remove = function () {
        document.removeChild(this.el);
    };

    Modal.prototype.footer = function () {
        var footer;
        app.utils.forEach(this.el.childNodes, function () {
            if (this.className === 'footer') {
                footer = this;
                return false;
            }
        });
        return footer;
    };

    app.modal = {
        ctor: Modal,
        create: function (title) {
            return new Modal(title).init();
        }
    }

}(app));

(function (app) {

    var Dialog = function (title, actions) {
        if (actions) {
            this.actions = actions;
        }
    };

    Dialog.inherits(app.modal.ctor);

    Dialog.prototype.addAction = function (action) {
        var button = document.createElement('button');
        button.value = button.innerText = action.title;
        button.onclick = action.fn;
        this.footer().appendChild(button);
    };

    Dialog.prototype.init = function () {
        app.modal.ctor.prototype.init.apply(this);
        app.utils.forEachWith(this.actions, this, this.addAction);
        return this;
    };

    Dialog.prototype.actions = [];

    app.dialog = {
        ctor: Dialog,
        create: function (title) {
            return new Dialog(title).init();
        }
    }

}(app));

(function (app) {

    var Confirm = function (title, ok, cancel) {
        this.title = title;
        this.actions = [
            {
                title: 'Ok',
                fn: function () {
                    // ok()
                    console.log('action.ok')
                }
            },
            {
                title: 'Cancel',
                fn: function () {
                    // cancel()
                    console.log('action.Cancel')
                }
            }
        ];
    };

    Confirm.inherits(app.dialog.ctor);

    app.confirm = {
        ctor: Confirm,
        create: function (title, ok, cancel) {
            return new Confirm(title, ok, cancel).init();
        }
    }

}(app));

var visible = false;
var c = app.confirm.create('Do you want to remove this?');
document.getElementById('toggle').onclick = function(){
    if(!visible) {
        c.show();
    }else{
        c.hide();
    }
    visible = !visible;
}