[rand01m]

var arr1 = [0, 1, 2, ["a,b,c"], "aaaa", [["d,e,f"], 4, 5]];
var arr2 = ["blabla", "blabla", "blabla"];
arr2[0] = arr1.slice();
alert(arr2);
//[[0, 1, 2, ["a,b,c"], "aaaa", [["d,e,f"], 4, 5]], "blabla", "blabla"]