Mashups using ArcGIS API for JavaScript

In web development, a mashup is a web page or application that combines data or functionality from two or more external sources to create a new service. Using SaaS – Software as a service.

The services used in the mashup sample below are ArcGIS Server REST API services.
REST (= Representational State Transfer ) is a easy way to use ArcGIS services using URL commands in webbrowsers.
There are services that respond with a simple Yes/No or True/False. There are also services that respond with a list of objects within a given polygon for example.