I'm developing a web page with an interactive chess tree-diagram. Feedback?

It is a really nice idea, I just looked at it.
Only complaint of mine is that the curved lines instead of simple straight ones makes it look a bit confusing after a while.
Still, great work, time to memorise stuff, no more excuse for me. 

FWIW, I like the curved lines.

A general design principle might be to allow customization (via Options) of everything that a) might be worth customizing and b) can be done cleanly, while providing sensible defaults.

For example, I'm not sure the absolute popularity % figures are more useful than relative ones. And given that the choices are ordered with most popular at the top anyway, it might be desirable to be able to turn them off (or change them to relative %, or colour code them, or apply a threshold so that very rare moves aren't shown, or... there are a lot of options one could offer).

Lots to think about.

The world needs more people like you. That's basically the next 10 years I'm spending right there.

You're right. The popularity %'s aren't the best alternative. I'm probably going to make the nodes color-coded based on sum of multiple criteria, like win-rate and popularity and computer evaluation or something. I put an option to deactivate the %'s for now.

Meanwhile, I put copy & paste PGN's to the app.

If you are interested, I have color-coding code that turns a value into a color (RGB triple) based on:

scale (min value to max value), and

color scale compactly represented as ASCII string, e.g. "01" is a greyscale from black to white, "VCYR" is a rainbow spectrum that blends from violet to red via cyan and yellow, "B1R" goes from blue to white to red and is useful for showing negative versus positive values with the most extreme values being primary colors and small values being more pastel shades (zero being white=no color), etc. etc.

(I haven't seen this idea before. Color scales are usually specified by names that expand to 128 or 256 color palettes that need to be stored/specified individually, and are usually created via a graphical interface in a rather laborious and non-intuitive way. My method allows users easily to experiment with alternative color scales just by typing letters. Those few letters/bytes are how the color scale is stored, compared to the hundreds of RGB values of the typical method.)

Certainly the most beautiful 'opening explorer' I've ever seen.

 Any further update on this? I go to this site daily, and use it for a lot of my building work. It is one of the most conceptually descriptive ideas I have ever seen, and lets me visualize what an opening "mean" more than anything I have ever seen. I registered and plan to donate. Is this meant to be a long term app? Two incredible addititon would be a formattable note/comment box that floats under your custom tree, that allows you to type in all strategic plans and goals of this particular part of the branch - i.e., after 4.Nxf6 in the Ruy Lopez Exchange, that that node, you'd see your plan come up in text form. Maybe an updating move list of the current line, and an expandable/collapsable outline form XML type stucture to the right maintaining your treck into the lines. I can provide examples if wanted. But nothing like this exists. 

Thanks! I'm hoping to get to make a major update by the end of the year. I will redo most of the code, which will make the trees much deeper and faster, and will speed up future development.

You can send examples to admin@chesstree.net, I might implement this idea after the rework.

Absolutely. I am glad you are still working on it and interested in it. There are few original ideas but this is one of them. There is nothing on the internet, and no software available that does this. It is awesome and I hope to see it around for a long time. 

 More traps and thousands of pgn games you can use at http://billwall.phpwebhosting.com/

Glad I stumbled across this today whilst looking to figure out how I will go about building out my opening book - a great resource and no apology here for resurrecting a 6 year old thread :-). Great job matey and thank you

It's the best tool I've ever seen for studying chess, thank you very much for the site, me and a buddy here from chess.com are trying to study the sicilian in deep, this will be of so much help, thank you very much Jex!!

I just discovered this today. Phenomenal! Thank you for developing it. It's far more instructive and goes much deeper than the openings explorer.

Hi. Thank's alot for your effort. please add the ability to generate opening tree from specific pgn file. I want to generate my real opening repretoire from my games pgn file.