How to write to a datatable from Javascript

I have table with two fields like so
REF QTY HD001 2 HD002 7 I retrieve via sql query and bind to gridview that contains itemtemplate to allow one of the values to be editable like so
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" onrowdatabound="GridView1_RowDataBound"> <Columns> < Go to the complete details ...