Link: http://www.nitobi.com/products/grid/
Source Author or Organization: Nitobi

Nitobi Grid is a high performance, cross-browser Ajax spreadsheet component for displaying and editing tabular data in a webpage. Using Nitobi Grid, users can easily resize columns, copy and paste data, navigate with a mouse or keyboard, perform in-place editing and scroll through huge datasets, just as if they're working with a desktop application like Excel. With minimal coding, Grid delivers slick, responsive, interactive data editing in a dynamic user-interface.