How to make a dropdown readonly using jquery?

$('#cf_1268591').attr("disabled", true); 

drop down is always read only . what you can do is make it disabled

if you work with a form , the disabled fields does not submit , so use a hidden field to store disabled dropdown value

I had the same problem, my solution was to disable all options not selected. Very easy with jQuery:

$('option:not(:selected)').attr('disabled', true);

Edit => If you have multiple dropdowns on same page, disable all not selected options on select-ID as below.

$('#select_field_id option:not(:selected)').attr('disabled', true);