Many years ago I helped write https://www.multisim.com It's a full SPICE based simulator done entirely clientside
Cool, thank you for sharing. I am interested in simulators, especially in simulators of analogue circuits. Do you have any recommendations on where to start reading about algorithms that lie at the core of simulators? Also, how was the experience developing such product with JS?
For information about the theory behind this, see Electronic Circuit & System Simulation Methods by Pillage