This is a basic example of using JSON and AJAX. AJAX is used to request the data and it is returned in JSON format. The JSON data is then evaluated and a chart created using it.
<script src="RGraph.common.core.js"></script> <script src="RGraph.line.js"></script>Put this where you want the chart to show up:
<canvas id="cvs" width="600" height="250">
[No canvas support]
</canvas>
This is the code that generates the chart:
<script>
/**
* Ths window.onload function initiates the AJAX request. The AJAX page is: http://www.rgraph.net/getdata.html?json
* If you view this in your browser you'll see that all it does is output a JSON object (a JavaScript object).
*/
window.onload = function ()
{
RGraph.AJAX.getJSON('/getdata.html?json', drawGraph);
};
/**
* This is the AJAX callback function. It splits up the response, converts it to numbers and then creates the chart.
*/
function drawGraph (json)
{
// Set the JSON on the window object so that the button below can show it to the user.
window.__json__ = json;
// Now draw the chart
var line = new RGraph.Line({
id: 'cvs',
data: json.data,
options: {
textAccessible: true,
hmargin: 10,
linewidth: 2,
ymax: 100,
labels: json.labels,
gutterLeft: 35
}
}).draw();
}
</script>