I have used ajax in the code which works perfectly and give me json or array which ever I want as an output.
the code I have used is,

xmlhttp=new XMLHttpRequest();

xmlhttp.open(GET,http://map_ajax_control.php,false);

xmlhttp.send();



var test = xmlhttp.responseText;

alert(test);

This test variable gives me json/array.

I want to get the data which I received in the test variable in the JavaScript array.

The question is, how can I decode json data in javascript array?
I have used the code as,

var output = new Array();  

output = json_decode(xmlhttp.responseText);

but this code is not giving me any output.

How can I do this two things?