I have been doing a research and want to share what I have found out. I have come across three major HTML5 libraries that would suit the needs of an isometric game. I hope the resources and insights are useful to future indie developers. If there are untruths and misconceptions below, I will be grateful if you correct me.
I will start with my journal first and then make a short list of pros and cons in the bottom.
The first HTML5 framework for an isometric game I came across was Cocos2D-HTML5.
First I stumbled into this example. Later on I saw Cocos2D-HTML featured in Intel® XDK
And third the isometric examples under "Tilemap Test" in the test cases: http://cocos2d-x.org/js-tests/
So I decided I will replicate the movement in an isometric environment in my own project and continue from there. And soon enough I could load any of my isometric Tiled maps in a browser and walk around. But then I found out that the TMX map functionality is very incomplete for isometric maps made with Tiled Editor. Most importantly there is no tileset offset available so you can't use objects larger than a single tile. I decided I can expand the functionality when it comes to isometric tiled maps. After all I can't expect that they have all the tools that I require for my needs.
I set expanding the Tiled Editor functionality for later, and start from a more basic point for now. I was going to start from a normal character sprite walking around. And then I found out the large community around this framework mainly writes in Chinese and uses some Chinese version of github. And so I can't find help for even the simplest of things which is keyboard movement and character animations. Frustrated by the lack of community in Cocos2D-HTML, I decided to scout around for another framework before committing.
Next on my list was Phaser, of which I found out about from these boards. The fact that it has a big and active community is very appealing. A little into looking at Phaser I found this Isometric plugin and became full of hope. Especially this example which could be the basis of a great isometric game. Using Phaser for a big project was a point proven by big games like Feudal Wars and Wild Terra. Two great games that are both isometric and made with Phaser(mostly).
Unfortunately there was no inbuilt support for maps made with the Tiled Editor. However there is another plugin that would load an isometric Tiled map which is outdated. The creator of this plugin is working on a new version that will come about soon and will work perfect with Tiled isometric maps. https://github.com/englercj/phaser-tiled "It's in the thin-tiles thread" he wrote "just bare with me". I got a little discouraged when I read several topics, about how Phaser's tileset is not fit for isometric maps and how both the developers of Feudal Wars and Wild Terra had to write their own modifications in order to use isometric tilemaps. Also, the great isometric plugin, the one that I mentioned first, is not good for maps larger than 10x10 tiles, because it uses a Sprite entity rather than a tile entity for each isometric tile, and this hinders the performance for larger maps.
Finally I got to Isogenic. As you may guess from the title, this framework has perfect support for isometric games. It has only some support for the Tiled Editor, but that is understandable since it supports a whole new level of isometric 2.5D which the Tiled editor does not. Once I went through most of the video tutorials I was able to run all the Node.js servers and play the multiplayer examples. The engine lacks a lot of the features that other engines have, but has a lot of multi-player features.
- Tiled Editor (Good): It is important that you can load map files straight away. No exporting, no adjusting. It is not perfect when it comes to isometric projection though.
- Community (Excellent): Phaser has a great community. A lot of open topics and discussion. A lot of the people I contacted personally with questions found the time and generosity to answer them.
- Cross-platform (Good): Not as native as Cocos2D, but with help from Intel XDK there is a very good performance. There is probably an even better way but I haven't searched yet.
- Tiled Editor (Poor): No inbuilt interpreter for the maps format and support for isometric tiles at all. There is hope however once Chad's plugin is ready.
- Other: It is possible to use 3D sprites with tree.js which will save the App loads of memory.
Isogenic Game Engine:
- Community (Poor): Author is very helpful and everything is well documented and supported with tutorials. But the community needs to grow a little more.
- Cross-platform (Poor): Certainly you can run the game on mobile since it is HTML5, but as to the best way in this case, I have no idea yet.
- Tiled Editor - (Poor): IGE is not a stranger to the Tiled editor, but it supports it very scarcely. You need to export your map, and then you need to make your own extension to use large tiles (trees and walls).
- Other: It really has amazing multiplayer and server-side functionality. It has some good path-finding. It has great 2.5D objects, more than tiles with an offset.
If you use Cocos2D-HTML5, there will be good prospects for your game on mobile as it will run as a native app. Decide how cross-platform you want to go in the future.
If you use Phaser you will struggle to achieve an isometric environment, but everything else in your game will be much easier. Decide how isometric you want to go in the future.
If you use IGE you will cover a lot of ground fast, with a flying start from an isometric environment. But after that you may hit a wall if you want to expand with functionality unexplored in the engine, such as spine animation or 3d sprites. Decide how classically isometric you want to stay in the future.