ArcGIS API For Flex and ArcGSI API for Javascript

[ManishGohil]

Hi,

   I am very excited about migrating our front end application from Web ADF to Flex.
   We are seeing that we also have ArcGIS JavaScript option.
   Can anyone list the advantages and disadvantages of Flex over JavaScript?

   Any help .. highly appreciate your help in advance.

Thanks
Lala Rabari

[ReneRubalcava]

I'll chime in with my experience.
Flex API:
- cross browser compatible, as in will function the same regardless of browser used.
- can handle large amounts of data better. When it comes to drawing of graphics on the screen or loading RemoteObjects, Flex can usually handle these items better than JavaScript.
- coming from Web ADF as you said, AS3 is much more familiar as language. Compiled and probably easier to learn coming from C#/VB.

JavaScript API:
- simplicity is key. Will run fine in most browsers, but can require some massaging if you want it to look/function same across all/many. IE6 will usually melt.
- if you are looking at mobile focused sites/apps, I think the JS API wins here. Will run pretty much the same across all phones/tablets, if you are mindful of some CSS3 funkiness.
- JSON is fast and lightweight. If you are pulling simple data requests, the dojo library the API is built on is built for data.

That's in my experience and opinion and could be completely off-base from what other people are doing.

You should also take a look at this recent posting from ESRI UC.
Which API should I use: JavaScript, Flex, or Silverlight?