When the chart is displayed - saveChartAsImage function is called and it gets PNG image of a chart.
Then this image is passed to "save.php" script which puts a PNG image of a chart to the server "temp" folder.
For demo purposes this image is shown in a new window after that.
If you see a text of PHP function in JS Alert Window and do not see any image in pop-up window - it means that you are launching the sample on a local PC or your server is not PHP enabled