Transaction calling using JavaScript

Hello,

I have a requirement. I am calling an IGrid applet. The grid applet displaying the content in a table.

The user is selecting the row and the row content should have be been retrieved and send as input parameter for a Transaction . The transaction is an RFC call.

The one return value (Suppose XYZ)of RFC will replace the selected row one column (cell ) content with XYZ and display in the grid.

My questions are.

1. How to call /execute the transaction and get the returned value in Javascript?

2. How to replace the content of a cell of the selected table?

Regards.

Anshul