alert("ab;01;41:cd;22;a0;0".replace(/(\d);(\d)/g, function (str, p1, p2, offset, s) { return p1 + "," + p2; }));
alert("ab;01;41:cd;22;a0;0".replace(/(\d);(\d)/g, "$1,$2"));
alert("1;2;4ab;01;41:cd;22;a0;0".replace(/(\d);(?=\d)/g, "$1,"));