The JK flip-flop is very similar to the RS flip-flop. The J input behaves like the S input, the K input like the R input. The only difference is when J and K simultaneously switch to 1. In an RS flip-flop the result in this case is not defined.
In a JK flip-flop on the other hand, when J and K are both equal to 1, the result changes for each Clk pulse.
This you can discover for yourself. Use the C-MOS IC 4027, on which you find a preprogrammed JK flip-flop...
In the next experiment, you learn about yet another class of flip-flops.