there is currently nothing in javascript to merge 2 arrays into 1 array (in sequence).
so I propose 
Array.concatArraysToArray([Array...])

I don't know how javascript works internally with arrays, so I don't know how the specification should look.  but the returned array should contain each argument's elements, in sequence.

Array.concat([item...]) won't do what I am looking for, it ruins arrays. maybe this should be a bug report?

one would hope you could do
var arr = Array();
arr = arr.concat(Array(1,2),Array(4,"jack"),Array(5,9,11));
and end up with arr containing Array(1,2,4,"jack",5,9,11), but that's not what you get. but this is what I am proposing.
I tried all the functions that looked promising. none work.