javascript - How can I get the length of a multidimensional array -

i have array follows:

$('#mmtable').data('armsitems').push([[],[],[]]); $('#mmtable').data('armsitems')[0][0]['productnr'] = 1; $('#mmtable').data('armsitems')[0][0]['title'] = 1; $('#mmtable').data('armsitems')[0][0]['description'] = 1; $('#mmtable').data('armsitems').push([[],[],[]]);  //------------------------------------------------- $('#mmtable').data('armsitems')[1][0]['productnr'] = 1; $('#mmtable').data('armsitems')[1][0]['title'] = 1; $('#mmtable').data('armsitems')[1][0]['description'] = 1; $('#mmtable').data('armsitems').push([[],[],[]]);  //------------------------------------------------- $('#mmtable').data('armsitems')[2][0]['productnr'] = 1; $('#mmtable').data('armsitems')[2][0]['title'] = 1; $('#mmtable').data('armsitems')[2][0]['description'] = 1;  alert( $('#mmtable').data('armsitems')[0][0].length );  // results --> 3  //------------------------------------------------- $('#mmtable').data('armsitems').push([[],[],[]]); $('#mmtable').data('armsitems')[0][1]['productnr'] = 1; $('#mmtable').data('armsitems')[0][1]['title'] = 1; $('#mmtable').data('armsitems')[0][1]['description'] = 1; $('#mmtable').data('armsitems').push([[],[],[]]);  //------------------------------------------------- $('#mmtable').data('armsitems')[1][1]['productnr'] = 1; $('#mmtable').data('armsitems')[1][1]['title'] = 1; $('#mmtable').data('armsitems')[1][1]['description'] = 1;  alert( $('#mmtable').data('armsitems').length ); // results --> 5  //---------------------------------------------------------------- 

how can number of elements in second field? e.g. :

[0][1]['productnr'] [1][1]['productnr'] 

i expect result 2-elements. how can it?

e.g. second field "1" follows: [x][1][x]

alert( $('#mmtable').data('armsitems')[x][1][x].length ); 

how many elements array contain (i expect result 2) ?

many in advance.

logically array should like,

['armsitems']['productnr'][0] ['armsitems']['title'][0] ['armsitems']['description'][0]  ['armsitems']['productnr'][1] ['armsitems']['title'][1] ['armsitems']['description'][1] // on.. 

then can length using,

alert(arr['armsitems']['productnr'].length); 

demo