Dijits have been tested to behave consistently in different browsers and comply with accessibility and localization requirements. The dijit framework is extensible, so with a little ambition you can even create your own dijits.
Your Web GIS applications may require the user to interact with the page outside of the map. For example, you might need users to enter some text, click a button, choose a value from a slider, or select an item from a dropdown list. Dijits give you a robust way to provide this functionality without writing the code yourself.
In the image below, the map, slider, buttons, and city seal have been combined into a dijit that a Web designer could add to the page with a line of code. The slider and the buttons themselves are individual dijits included in the larger dijit.
Dijits can also help users accomplish focused workflows, such as finding nearby dentists, selecting a site for a business, or generating a route. In this way, dijits are similar to “tasks” in the Web ADF.
Contributed by Sterling Quinn of the ArcGIS Server software development team