function json2array(json){
var result = [];
var keys = Object.keys(json);
keys.forEach(function(key){
result.push(json[key]);
});
return result;
}
var as = JSON.parse(jstring);
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);