用jquery选择一个选项，并且在select元素中还有一个onchange（）吗？

Question

I'm trying to select VISA in this selection, but it won't work. I've tried almost everything.

$('#creditcard_cctype option[value="VISA"]').click();
$('#creditcard_cctype').val("VISA");
$('#creditcard_cctype option[value="VISA"]').prop("selected", true);
$('#creditcard_cctype option[value="VISA"]').attr("selected", true);
$('#creditcard_cctype option[value="VISA"]').cttr("selected", "selected");

The problem is that the updateCreditCardType() function changes around the html file so I can obtain the CCV option. It just isn't selecting.

<select name="creditcard_cctype" id="creditcard_cctype" onchange="updateCreditCardType()" class="Field250">
    <option value="">-- Please Choose --</option>
    <option id="CCType_AMEX" class=" requiresCVV2" value="AMEX">American Express</option>
    <option id="CCType_DISCOVER" class=" requiresCVV2" value="DISCOVER">Discover</option>
    <option id="CCType_MC" class=" requiresCVV2" value="MC">Mastercard</option>
    <option id="CCType_VISA" class=" requiresCVV2" value="VISA">Visa</option>
</select>

Answer 1

Just trigger the change event to force the HTML-bound onchange handler to fire.

$('#creditcard_cctype').val('VISA').trigger('change');

jsFiddle demo: https://jsfiddle.net/c3sqhrma/

Answer 2

use this to set the value once the document is ready

$('#creditcard_cctype').val('VISA');

http://jsfiddle.net/c3sqhrma/2/