Q:

Can I run arcgis javascript code in Arcgis Desktop

Basically, what I am looking for is, I want to learn Arcgis javascript api. And I have Arcgis Desktop 10.3 Trial version installed on my pc. I have heard that javascript can be run only in Arcgis Server based web application. So is there any possibility to run this javascript code in Arcgis Desktop? If not, suggest me ideas on how to get a Arcgis Server Trial for practicing javascript api.
Thank you.

A:

No, you cannot use ArcGIS Desktop to run Javascript api app. It is a web based sdk. You can simple run it on any browser. The main things is you would need ArcGIS Server Services to display data on the map. 
To learn you dont need to have a server on your local, you can use arcgis online services. You can find more details on their website.
https://developers.arcgis.com/javascript/3/jshelp/

