jQuery / Programmatically Select an Option in Select Box

I'm currently using jQuery to return some JSON results. Once these results are returned, I'm using them to pre-populate fields in my form.

However, I need some help in pre-selecting items in a drop down box. For example, I have a select box (this is shortened):

<select id="startTime">
<option value="14:00:00">2:00 pm</option>
<option va开发者_如何学Pythonlue="15:00:00">3:00 pm</option>
<option value="16:00:00">4:00 pm</option>
<option value="17:00:00">5:00 pm</option>
<option value="18:00:00">6:00 pm</option>
</select>

And if my JSON value is:

 var start_time = data[0].start  // Let's say this is '17:00:00'

How can I, using jQuery, make the option with value '17:00:00' selected?

 <option value="17:00:00" selected="selected">5:00 pm</option>

update:

As of jQuery 1.9, jQuery has updated this functionality. The "selected" state of an option is actually a property, therefore jQuery has changed this to use the .prop() method. Syntax is very similar and easy to switch:

$('#startTime option[value=17:00:00]').prop('selected', true);

See http://api.jquery.com/prop/#entry-longdesc for why it needs to pass true.

Older jQuery

$('#startTime option[value=17:00:00]').attr('selected', 'selected');

or

$('#startTime option[value='+ data[0].start +']').attr('selected', 'selected');

$('#startTime').val(start_time);

It's just $("#startTime").val(start_time);

$('#startTime').val(start_time);

If you want to trigger selected change event after selecting option:

$('#startTime').trigger("change");

UPDATE

As of jQuery 1.9, jQuery has updated changed this functionality. The "selected" state of an option is actually a property, therefore jQuery has changed this to use the .prop() method. Syntax is very similar and easy to switch:

$('option[value=17:00:00]').prop('selected', 'selected');

For some reason for me it works like this:

$('#startTime').val(''+data[0].start+'');

Additional Information for jquery mobile users (1.3.0):

Here's a similar example.

If you try the example above with jquery 1.9.1 and jquery mobile 1.3.0 you can see that it's not working unless you add a

$("#location_list").selectmenu("refresh");

Keep that in mind when working with jquery mobile. It gave me a lot of headache

var varValue="17:00:00";
$("#startTime").ready(function(){ 
   $("#startTime option[value='"+varValue+"']").prop("selected", "selected"); });

Works for me on jQuery 1.10