http://www.packtpub.com/articl.....gin-jqgrid

This tutorial uses JSON as a data exchange format, so it was useful to learn about this way of exchanging data, rather than the usual XML examples.

Note:  To get the tutorial to work, you'll need to download the source files, which are actually located where you download the code for the book.  (The code as shown in the tutorial doesn't work).  The grid tutorial is Chapter 8 in their book, Ajax & PHP, Building Responsive Web Applications.

Apparently, their code doesn't allow you to add New Rows, it just allows you to edit existing rows.
But, it's a good start.

I'm using the jqGrid plugin, and I'm able to fill my grid with data from a database. 
The documentation does a good job of explaining this and showing code examples.

However, I don't see any server-side code examples anywhere for adding a row.

Maybe I overlooked it?

thanks!