1)Is it possible to automatically save the chart as image in specified folder after chart has been rendered?.In this case,chart should be download without user Interaction. Can I use “ExportEnabled=true” option?.
1)Is is possible to get the chart data in base64 format?
You can change save.download = 'CanvasJS.png'; in first example to your desired name. Here CanvasJS.png is the image-file name. And in the second example, you can use exportFileName to set image-file name.
Download location setting is a part of browser setting, it varies from browser-to-browser. You can change it under browser settings. Check these links to change/manage download location in chrome and Firefox.