selecting an option from a dropdown with jQuery

JQuery - dynamic select for drop downs

//on drop down selection, select the element in the hidden input
$('.qa-filter-select ul a').live('click', function(){
  $('#category option[value=selected]').val('')
  $('.qa-filter-select option').eq($(this).index('.qa-filter-select ul a')).val('selected','selected');
  $('.qa-filter-select .selected').html($(this).html());
});

Intended to set the selected attribute to 'selected', but instead it just sets the value attribute to 'selected'. Also tried .attr('selected', 'selected') too

Solution:

$('.qa-filter-select ul a').live('click', function(){
$('#category option')['selected'] = false;
$('.qa-filter-select option')[$(this).index('.qa-filter-select ul a')]['selected'] = true;
$('.qa-filter-select .selected').html($(this).html());
});

Seems like .attr('selected','selected') should do this, but it doesn't. This doesn't visibly manipulate the dom though.