best way to generate empty 2D array

Question

is there a shorter, better way to generate \'n\' length 2D array?

var a = (function(){ var i=9, arr=[]; while(i--) arr.push([]); return arr })();

a // [ [],         


        

Answer 1

var a = [];
var max_length = 10;
for(var i = 0; i < max_length; ++i){ 
    a[i] = []; 
}