Creating web applications with the ArcGIS API for JavaScript
If you want to embed lightweight mapping functionality into a web application, or if you're just getting started with ArcGIS for Server development, consider using the ArcGIS API for JavaScript. All you need is a server or portal available whose maps and tools you can use in your application. Esri provides some sample servers for this purpose. To get started, see the ArcGIS API for JavaScript home page in the ArcGIS Resource Center.
The ArcGIS API for JavaScript is powered by a back-end REST API that is able to retrieve information statelessly from the server. When you run the application, the code runs in the browser instead of having to run on the server. This provides a quick and clean client experience. The ArcGIS API for JavaScript is built on top of the Dojo JavaScript toolkit, so you don't have to worry about accommodating browser idiosyncrasies in your code; the framework handles it for you.
You can use the ArcGIS API for JavaScript even if you have little or no coding experience. Copy and paste the example code into your HTML pages to add mapping functionality.
When writing your apps with the ArcGIS API for JavaScript, you can reference intelligent web maps that you've authored using ArcGIS.com or Portal for ArcGIS. In fact, using these interactive environments to create your web map can save you a lot of coding. If you don't reference a web map, you'll need to provide the URLs to individual services that you want to display. You can use the Services Directory to find these web addresses.