An alternative for jsFiddle is Plunker, where you can create code and then run it. Alternatively you can browse between the codes (called Plunks) added by other users.
So this is a bit sophisticated and similar to a website: write here, copy the code (all the files) and add it to your site. And because it is similar to a live website, you can use other JS libraries too, for example GoogleCharts.
I’d say give it a try too – and when not to code then to browse among the plunks.
OK, recently I ran over this site, and I have to tell it is really great.
And naturally you can share the code among your “followers”, they can edit and fork (reuse) it to help out with your problems. So I’d encourage you to give it a try. If you cannot decide which JS Framework to use: then it is a must.
Well, beside this post I’m currently trying out AngularJS as a nice alternative for dynamic web applications. Who knows, maybe I will use it on daily basis (in work and private too).