After you select a subset of data points in a select-scatter chart and click Submit, the selected data is sent to a server-side script, or a JavaScript function, for further processing.

In this section, you will be shown how the updated data is read using the JavaScript functions present on the same page.

After the chart is rendered, to access the chart data as an array, the following function is called:

//Get a reference to our chart
var chartObject= FusionCharts("chartId");    

//Now get the data as array. 
var arrData = chartObject.getData();

You first need to get a reference to the chart object. You can do so using the FusionCharts item reference method. Next, to get the data as an array, call the getData() method of the chart. This method returns the data of the chart in a two-dimensional array.

Given below is a brief description of the structure of this array:

Now, from this chart, if you select three data points from the Televisions dataset and five from the Cell Phones dataset and then return the data of chart as an array using the getData() method of the chart object, the tabular mapping of the array returned can be traced as under:

If you map this with the JSON data, you will find the following:

• Each dataset is returned as a single row in the array

• The first column of each row contains the dataset index

• The rest of the columns contain the ids of the selected points of that dataset

• The length of each row's array (horizontally) can be different, depending on the number of data points chosen for that dataset

Reading JSON Data from the Chart

The chart also provides a method to read the selected data in the JSON/XML format. This method is named as the getJSONData() and can be invoked as under:

//Get a reference to our chart
var chartObject= FusionCharts("SelectChart"); 

//Get the data from chart 
var jsonRtn = chartObject.getJSONData();

//Show it to user in alert box
alert(jsonRtn);

The function getJSONData() returns the selected data. This function is also used to retrieve the complete data from the chart. To get the complete data from the chart you need to pass false as a parameter to the function. For example, var jsonRtn = chartObject.getJSONData(false);

A select-scatter chart configured to show how the selected data is retrieved and updated looks like this:

The data structure needed to configure the above chart is given below:

• JSON
• XML

There! You have now seen how you can retrieve and update selected data from a select-scatter chart.