If you receive recurring alerts that your browser is running low on memory it probably means your computer is below the minimum specs. WebGL 3D engine renders the simulation in real time and uses memory via the browser's tab. In continuous sessions your browser may run low on memory and will force you to restart.
While this is not optimal, by closing your browser and reopening CoderZ, you will probably be able to run for a while before your browser will run out of memory again.
A permanent solution would require upgrading your machine, or using a computer the meets the minimum requirements for CoderZ.