i am afraid jdeline did not understand the problem at hand
here... sure, the example is a good one of the use of populating
select boxes with query results, but it does not show how to
achieve what Nick201 want to achieve.
if i understand you correctly, Nick201, you need to be able
to select multiple entries in your selectbox. if one of the
selected entries is 'John', you need to un-select any other
selected entries. if 'John' is selected, and then another selection
is made, you need to un-select 'John'. am i correct?
you do need to do it through javascript. let me know if i
understand you right and i will post some code for you. you can do
it with either select box or checkboxes (whihc i think will be
easier as their values are easier to parse).