How do you select a particular option in a SELECT element in jQuery?

A selector to get the middle option-element by value is

$('.selDiv option[value="SEL1"]')

For an index:

$('.selDiv option:eq(1)')

For a known text:

$('.selDiv option:contains("Selection 1")')

EDIT: As commented above the OP might have been after changing the selected item of the dropdown. In version 1.6 and higher the prop() method is recommended:

$('.selDiv option:eq(1)').prop('selected', true)

In older versions:

$('.selDiv option:eq(1)').attr('selected', 'selected')

EDIT2: after Ryan's comment. A match on "Selection 10" might be unwanted. I found no selector to match the full text, but a filter works:

 $('.selDiv option')
    .filter(function(i, e) { return $(e).text() == "Selection 1"})

EDIT3: Use caution with $(e).text() as it can contain a newline making the comparison fail. This happens when the options are implicitly closed (no </option> tag):

<select ...>
<option value="1">Selection 1
<option value="2">Selection 2
   :
</select>

If you simply use e.text any extra whitespace like the trailing newline will be removed, making the comparison more robust.

You can just use val() method:

$('select').val('the_value');

None of the methods above provided the solution I needed so I figured I would provide what worked for me.

$('#element option[value="no"]').attr("selected", "selected");

By value, what worked for me with jQuery 1.7 was the below code, try this:

$('#id option[value=theOptionValue]').prop('selected', 'selected').change();