Export iBook to HTML

Hi, I have created an iBook, but since not all users do have an Apple device to read it I need to offer the content as HTML webpage, too. Is there any possibility to export the iBook to HTML Code? It doesn't matter if the Widgets don't work, I will rebuild them on the webpage. But it would be very annoying if I have to copy paste everything out of the iBook into the HTML webpage manually. The export as a plain text document isn't really a good solution since the images will not be exported (and there are a lot of images).

Many thanks for your help!