[bes]

//например, для 3 функций
var a = 0;
function toggle3() {
  switch (a) {
    case 0: {f1(); break}
    case 1: {f2(); break}
    case 2: {f3(); break}
  }
  if (a == 2) a = 0; else a = a + 1;
}

//или так
var a = 0;
function toggle3() {
  switch (a) {
    case 0: {f1(); break}
    case 1: {f2(); break}
    case 2: {f3(); break}
    default: {f1(); a = 0}
  }
  a = a + 1;
}