How to convert JSON object to JavaScript array?
var json_data = {"2013-01-21":1,"2013-01-22":7};
var result = [];
for(var i in json_data)
result.push([i, json_data [i]]);
var data = new google.visualization.DataTable();
data.addColumn('string', 'Topping');
data.addColumn('number', 'Slices');
data.addRows(result);
http://jsfiddle.net/MV5rj/
If you have a well-formed JSON string, you should be able to do
var as = JSON.parse(jstring);
I do this all the time when transfering arrays through AJAX.