I have a json encoded array

{"users":[{"row_id":"1","0":"Tom","1":"Cruise","2":"tomcruise","3":"1","4":"231","5":"10","6":"Old Lyme","7":"235","8":"532","9":"12"},{"row_id":"21","0":"mrs. tom","1":"cruise","2":"place","3":"0","4":null,"5":null,"6":null,"7":"6","8":"42","9":"0"}]}

My javascript is...
Code JavaScript:
var search 	        = eval('(' + resp + ')');
var search_wrap 	=[];
 
alert(search.length);


When my function returns the json encoded array, my alert is undefined. Is this because my array is multidimensional?

The pre of my array is...

Array
(
[users] => Array
(
[0] => Array
(
[row_id] => 1
[0] => Tom
[1] => Cruise
[2] => tomcruise
)

[1] => Array
(
[row_id] => 21
[0] => mrs tom
[1] => cruise
[2] => mrstomcruise
)

)

)