how to read parse server ParseResponse code example
Example 1: js string to object
JSON.parse()
Example 2: json to array javascript
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);