How do you plan to solve it?
module jk_ff ( input CLK, input J, input K, output reg Q ); always @(posedge CLK) begin if( J == 0 && K == 1) Q <= 0; else if ( J == 1 && K == 0) Q <= 1; else if ( J == 1 && K ==1) Q <= ~Q; else Q <= Q; end endmodule