This is also great skill to have for the GIS professional. There are a lot of great and free resources to get you started. Below are a list of some sites. Hopefully at some point there will be examples.
For ESRI users, you need to know that there are 2 versions of the API that are currently in use. As of the summer 2017, the 4.4 API has been released, BUT not all the widgets are available (such as editing). I have still been working with 3.21
| Type | URL |
|---|---|
| Guide and API Reference | ArcGIS API for JavaScript 3.21 |
| Guide and API Reference | ArcGIS API for JavaScript 4.4 |
| Template | CMV - The Configurable Map Viewer |