Array length in 2d-array

programming flash
1

I was wondering can I use the array.length command to somehow find out the length and ‘width’ of the array?
.length shows how many lines there are but can I somehow use it to view how many entries are on each line?

var mappi = [
["0","1","0"],
["1","1","1"],
["1","1","1"],
["0","1","0"]
];