JSON get value at first index -

i stuck @ , have no idea script clear. see php code:

<?php  $arr = array();  $i = 0;  while($i < 10) {    $arr[] = $i;    $i = $i + 1; }  echo json_encode($arr);  ?> 

it returned ajax function :

[0, 1, 2, 3, 4, 5, 6, 7, 8, 9] 

suppose stored in d javascript variable how can point first value so, stores 0 variable.

if this:

success: function(d) {     var = d[0]; } 

it returns null.

i don't know how explain question because not @ english.

try this:

success: function(d){     $.each(d, function(x,y){        var = y['field'];     }); }