Well, most of those use the ACE editor component, rather than the CodeMirror editor component.
I don't know why and obviously, this isn't true for everybody, but i'm always at war with CodeMirror. It auto-outdents and reformats things exactly how i do not want them. Whenever i'm forced to use CodeMirror, i'm undo-ing more than i'm typing and swearing about once every 5 seconds.
So, if you are one of those people, like me, that is always getting furious at jsFiddle, try an ACE based alternative.
Interestingly, once you realize that these code-editor components are quite simple to implement on a web-site, you also understand why there are 100+ jsFiddles clones. Most, if not all web-devs should be able to create one in half a day. They may think it's harder before they begin, but they will be pleasantly suprised.
This is likely also, why we're seeing a new "Online IDE" every week these days. GitHub's new Atom.io editor is the first one in a long time, to not use CodeMirror or ACE at its core.
I don't know why and obviously, this isn't true for everybody, but i'm always at war with CodeMirror. It auto-outdents and reformats things exactly how i do not want them. Whenever i'm forced to use CodeMirror, i'm undo-ing more than i'm typing and swearing about once every 5 seconds.
So, if you are one of those people, like me, that is always getting furious at jsFiddle, try an ACE based alternative.
Interestingly, once you realize that these code-editor components are quite simple to implement on a web-site, you also understand why there are 100+ jsFiddles clones. Most, if not all web-devs should be able to create one in half a day. They may think it's harder before they begin, but they will be pleasantly suprised.
This is likely also, why we're seeing a new "Online IDE" every week these days. GitHub's new Atom.io editor is the first one in a long time, to not use CodeMirror or ACE at its core.