HTML5 and Qt are both terrific technologies. Choosing one for your next project is challenging. This white paper by sequality software engineering will increase your awareness of which technology better fits a given situation, when it makes sense to combine the two, and how to plan for an open,scalable architecture.
sequality's white paper compares
The focus of this white paper is on embedded devices and industry display panels. While a lot of the basics apply to a desktop or mobile environment, some of the nuances are more relevant for the embedded and industrial fields.
For more helpful comparisons of Qt and HTML visit this webpage.