Lock HTML select element, allow value to be sent on submit

This works:

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

jQuery will still be looping through the elements behind the scenes, but I seriously doubt you will have performance issues unless your select has thousands of elements (in which case your usability issues will far out weigh the performance issues). The original code must have been doing something wrong.

Add a hidden field to your form and onsubmit take the value from the select and place it in the hidden field's value

As per the HTML spec, readonly is not supported by the select tag

This works fine

<select disabled="true">
<option value="1">one</option>
<option value="2">two</option>
<option value="3">thre</option>
</select>