I want to create a indoor map application using HTML5 and JavaScript. I have created a simple road map application, but when I click to zoom in on any indoor compatible building
Looks like the JavaScript v3 API does not yet support indoor maps. But it might come.
The official page says it will be available: https://www.google.com/maps/about/partners/indoormaps/
"In addition to making the content available to our users in Google Maps, your indoor map will also be available through the Google Maps APIs for use in your mobile applications or website."