Click on a certain place to zoom into there. Note that the image will have to load again when zooming in. DO NOT try and zoom in by using two fingers, you might go somewhere unintended. To increase the detail, go into the code and increase the variable "detail" and vice versa. Detail starts at 100 by default.
The mandelbrot set is the set of complex numbers c, where when repeatedly applying z^2 + c (z is a complex number which starts at 0 + 0i), z does NOT explode to infinity. This specific example has 100 iterations, but you can go into the code and change it if you want.