CK Editor — 3.4 (Classic Version)
About This HTML Editor
This is a "Classic" version of the "CKEditor". Specifically, it's CKEditor 3.4.
CKEditor is an open source HTML text editor. Developers can use CKEditor in their own projects. For example, you could install CKEditor into your organization's content management system so that content providers can update the corporate website or intranet.
This version has since been superceded by more recent versions, however, you might find that this version works on browsers that have problems with the more recent versions.
Also, if you do have browser compatibility issues (or any other issue) with the CKEditors, you could try the TinyMCE Editor.
Setting up CKEditor
The same code is used for more recent versions too, such as this one.