I have reason to believe console.log and JSON.stringify can produce inconsistent views of the same object even if it was created in a straightforward m
Why don't you just use console.dir(obj) instead? Or use console.log(obj) and then click on the output / expand it?
Also when I try the following code:
var obj = {};
obj.players = {};
obj.players[0] = {color: "green"};
obj.players[1] = {color: "blue"};
obj.world = "xyz";
console.log(JSON.stringify(obj));
I always (Firefox, Chrome, Opera) get this as output:
{"players":{"0":{"color":"green"},"1":{"color":"blue"}},"world":"xyz"}
Furthermore it looks like your players object is actually an array. So you should better create it as such.
Update:
I just saw that you added a link to a JSFIDDLE demo, which empties the players object right after logging it. To my knowledge all web dev tools use some kind of asynchronous display, which results in an empty players object when using console.log(obj) or console.dir(obj). Firebug thereby offers the best results by displaying the object correctly using console.dir(obj).