Question

Is it possible to override the Image constructor in JS? So that, for example, every time a new Image() is created, a message is written to the console?

Answer 1

Try this:

(function () {
    var OriginalImage = window.Image;
    window.Image = function (width, height) {
        console.log('New image');
        return new OriginalImage(width, height);   
    }
}());

Not sure if it will work in all browsers.

Anyway it is not best idea to override built in types (unless you want to use it to mock/stub for test purposes).