Forms Data Controls :: Gridview Is Not Updating And Deleting Without ID Column?

I have a gridview in which update and delete is enabled.

I have the following fields in database table, which is binded to the grid view through sql datasource.

ID,Firstname,Lastname,Add,City,modifieddate. Here ID is primary key.

1. When edit and delete is enabled in the grid. The ID column is showing in the grid,which i don't want to show. But without that ID column the grid is not able to update and delete. Plz tel me how to update and delete without ID column in grid.

2. When ever any update is happen in the grid, the modifieddate should get updated. Here the date is not datetime.now , i need to use my own system date and time. Coz my server and system time has some difference.

I have use the following javascript to get system date and time, which is working fine. This date should be get and update in the modified column.

function displayTime() {
var m_names = new Array("Jan", "Feb", "Mar",
"Apr", "May", "Jun", "Jul", "Aug", "Sep",
"Oct", "Nov", "Dec");
var localTime = new Date();
var year = localTime.getYear();
var month = localTime.getMonth() + 1;
var date = localTime.getDate();
var hours = localTime.getHours();
var minutes = localTime.getMinutes();
var seconds = localTime.getSeconds();
var div = document.getElementById("TextBox1");
div.innerText = date + "-" + m_names[month] + "-" + year;
}