In this talk, we will present the state of the art and history of volunteer and, in particular, browser-based computing, will make a general introduction to evolutionary computation, and then how this type of algorithms can be adapted to run on ephemeral, distributed, asynchronous, and heterogeneous nodes. We will present our NodEO and jsEO evolutionary algorithm libraries and the result of some experiments using this platform. Finally, we will generalize and show a general methodology for doing scientific computing using JavaScript.