Javascript文字处理器/编辑器(或谷歌文档体系结构)

I thought it would be interesting to roll my own text editor a la Google Docs, purely for curiosity of course (nothing to do with reinventing the wheel). I've been wondering how applications like Docs and Zoho Writer can get advanced layout like separating text on different pages, or keeping headings together with their content, you know, things editors like I thought it would be interesting to roll my ow