Select Checkboxes in Datagrid and preview in new window

[Angela]

Hi

I have a datagrid with checkboxes besides a list of names.

What I want is for the user to select the checkboxes and press 'Preview'
and a new window opens with a print friendly list of the selected
contact details.

I can get the selected IDs via my server side code but can't target a
new window to open.

So I thought of using Javascript and concatenating the IDs (e.g.
2,4,6,8) and do a window.location = '...' but the checkboxes in the
datagrid do not have IDs associated with them.

Can I get the datagrid checkbox have the value of the contact IDs? Is
there a better way of achieving the above?

Thanks
Angela