A page with a live example can be seen [here](http://www.sveido.com/mermaid/demo/html/web.html). You can also look at mermaid in action using [jsbin](http://jsbin.com/faxunexeku/1/edit?html,output). If you want a live demo, there is an editor provided in the mermaid project or you can simply look at this [great editor](http://danielmschmidt.github.io/mermaid-demo/)
Many thanks to the [d3](http://d3js.org/) and [dagre-d3](https://github.com/cpettitt/dagre-d3) projects for providing the graphical layout and drawing libraries! Thanks also to the [js-sequence-diagram](http://bramp.github.io/js-sequence-diagrams) project for usage of the grammar for the sequence diagrams.