Read Sub-Grid cell value MS CRM 2013 !!!

Here is sample code to get sub grid cell value in MS CRM 2013.

function GetSubGridCellValues() {

    if (document.getElementById("SubGridName")) {

        var grid = document.getElementById("SubGridName").control;

        var ids = gridControl.get_allRecordIds();

        for (i = 0; i < ids.length; i++) {

            alert(gridControl.getCellValue('fullname', ids[i]));

        }

    }

    else {

        setTimeout("GetSubGridCellValues();", 2500);

    }

}