Yes there is, and it works quite well: http://www.jetbrains.com/editors/javascript_editor.jsp?ide=i...

For sure it has some oddities with the completion as it can't be sure what the prototypes are, but then it just lists functions from different prototypes which match your prefix.

Thanks. Those specific complaints from the link seemed more like quality of implementation issues of typical ECMAScript editors vs Adobe's ActionScript IDE. I can live without type inference in a dynamic language, but Visual Studio and Qt Creator have spoiled me on the other features.

  function DoStuff(foo)  //<<<<No information what type foo is
  {
    foo.DoA();  //No way to know what methods foo support
    foo.DoB();
  }

For most situations where it is possible to infer the type, Visual studio actually does a pretty good job on code completion, but no jump to definition.

WebStorm has jump to definition, re-factoring, code inspection that provides valuable auto-complete suggestions (and if you use JSDoc tags it can read those) and more: http://www.jetbrains.com/webstorm/features/index.html