Jquery modify select (multiple) value.

Question

I am aware that you can use .val() to change which options are selected in a select multiple=multiple but,

How can you simply select/deselect one option, without changing the state of the other options?

Answer 1

You do not have to use jquery for everything.

var el = $(..)[0];
el.options[i].selected = false;

Answer 2

In this case it's easiest to de-select the particular option:

$("#select option[value='"+val+"']").removeAttr("selected");