Before smartphones hit the market, AR was exclusively developed on computers. Later on, web applications appeared, first written in Flash and then in HTML5, but always requiring the webcam from a computer. Since the appearance of the ARCore (Google) and ARKit (Apple) toolkits, AR is also arriving on smartphones through the web.
WebXR Device API is one of the current standards that's working to provide the specifications for accessing both VR and AR from the web, including the use of devices' sensors or head-mounted displays (HMDs). This standard specification is being written by the World Wide Web Consortium (W3C) and it's currently under development. At the time of writing, the integration of AR in this WebXR specification is still unstable and thus it's not presented in this chapter. It is...