function test() {
    
    var applicationId= 0 ;  
    var myDataGrid = document.getElementById("<%=DataGrid1.ClientID %>");
    var TabLength = myDataGrid.Length;
     for(i= 1 ;i<TabLength;i++)
    {
        var el_chk_SelectItem = document.getElementsByName("DataGrid1:__ctl"+ i +":_chk_SelectItem");
        if (el_chk_SelectItem.checked=true)
        {
            var in_applicationId = document.getElementsByName("DataGrid1:__ctl"+ i +":_in_applicationId");
            applicationId = in_applicationId.value ;
        }
    }
alert (applicationId);
}