//var a = new Array("a", "b", "c");
//var b = new Array(1, 2, 3);
//var c = new Array(a, b);
//var d = new Array("str", 123, undefined, null, true, false);
//a.join();
a,b,c
//b.join();
1,2,3
//c.join();
a,b,c,1,2,3
//c.join(undefined);
a,b,c,1,2,3
//c.join(null);
a,b,cnull1,2,3
//c.join(false);
a,b,cfalse1,2,3
//a.join(NaN);
aNaNbNaNc
//b.join(5);
15253
//c.join(" + ");
a,b,c + 1,2,3
//c.join(b);
a,b,c1,2,31,2,3
//d.join("!");
str!123!!!true!false
