hi pls try this
<script type="text/javascript">
function Add(e) {
var grid = $find("<%=RadGrid1.ClientID %>");
var MasterTable = grid.get_masterTableView();
var row = MasterTable.get_dataItems()[index];
var txt1 = row.findElement("txt1").innerHTML;
var txt2 = row.findElement("txt2").innerHTML;</pre>
}
</script>