MediumEditor is a simple inline editor that is clone of Medium.com WYSIWYG editor. MediumEditor has been written using JavaScript, no additional frameworks required.
X-editable is a library that allows you to create editable elements on your page. It can be used with Bootstrap, jQuery-UI, jQuery only. It includes both popup and inline modes.
jQuery Tabledit is a inline editor for HTML tables compatible with Bootstrap. It is possible to edit inline like a spreadsheet or with buttons to change between edit and view mode.