This is an example of using GeneMO library to run a genetic algorithm in a web browser. GeneMO executes each iteration asynchronously to avoid blocking the browser's main thread. There is no need to use Web Workers, although they may be useful if you want to take full advantage of multi-core processors. The Source code of this example can be found in GeneMO Web Demo Github repository.
This example solves the Traveling Salesman Problem. It searches for the shortest path to visit 48 cities, given distances between each pair of these cities.