I don't know about Aptana Cloud (when I looked at it they had very bad Linux support) but their JavaScript IDE is pretty nice. My current project has (in the d

I don't know about Aptana Cloud (when I looked at it they had very bad Linux support) but their JavaScript IDE is pretty nice. My current project has (in the development version - cleaned up by the deployment scripts) about 10 source files and it handles auto complete for objects and methods quite well despite that. It breaks a bit on methods added via Object.prototype.method but as soon as you use them once its catches it and remembers it.