Loading google datatable using ajax/json - ajax

Question

I can't figure out how to load a datable using ajax/json. Here is my json code in a remote file (pie.json)
{
cols: [{id: 'task', label: 'Task', type: 'string'},
{id: 'hours', label: 'Hours per Day', type: 'number'}],
rows: [{c:[{v: 'Work'}, {v: 11}]},
{c:[{v: 'Eat'}, {v: 2}]},
{c:[{v: 'Commute'}, {v: 2}]},
{c:[{v: 'Watch TV'}, {v:2}]},
{c:[{v: 'Sleep'}, {v:7, f:'7.000'}]}
]
}
This is what I have tried so far but it doesn't work.
<script type="text/javascript" src="http://www.google.com/jsapi"></script>
<script type="text/javascript">
google.load("visualization", "1", {packages:["piechart"]});
function ajaxjson() {
jsonreq=GetXmlHttpObject();
jsonreq.open("GET", "pie.json", true);
jsonreq.onreadystatechange = jsonHandler;
jsonreq.send(null);
}
function jsonHandler() {
if (jsonreq.readyState == 4)
{
var res = jsonreq.responseText;
google.setOnLoadCallback(drawChart);
function drawChart() {
var data = new google.visualization.DataTable(res, 0.6)
var chart = new google.visualization.PieChart(document.getElementByI('chart_div'));
chart.draw(data, {width: 400, height: 240, is3D: true});
} // end drawChart
} // end if
} // end jsonHandler
function GetXmlHttpObject()
{
var xmlHttp=null;
xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
return xmlHttp;
}
Things work perfectly if I replace the 'res' variable with the actual code in pie.json.
Any help would be greatly appreciated.

Answer 1

Just a guess because I'm unfamiliar with the google objects you are using, but I'm pretty sure responseText just returns a string. JavaScript can't natively parse JSON (only XML to the best of my knowledge), so you'd have to eval("var res = " + jsonreq.responseText).
I hope this helps.

Answer 2

if I were in you, I'll use jQuery to save some code:
$.getJSON("pie.json", function(data) {
drawWanChart(data);
});
and here the function that draws your chart:
function drawWanChart(jsonData)
{
jsonData = jQuery.parseJSON(jsonData);
if(jsonData != null)
{
data = new google.visualization.DataTable(jsonData);
chart = new Google.visualization.Table(document.getElementById('chart_div'));
chart.draw(data, null);
}
}
Please refer to official documentation:
$.getJSON
PieChart on Google Playground