In this book you're going to use the ArcGIS API for JavaScript Sandbox to write and test your code. The Sandbox can be found at https://developers.arcgis.com/javascript/3/sandbox/sandbox.html and will appear as seen in the screenshot when loaded. You'll write your code in the left pane and click the REFRESH button to see the results in the right pane:
![](https://static.packt-cdn.com/products/9781787280526/graphics/assets/325f9afa-d022-4275-aa17-a706f71878e5.png)