javascript - 使用each()求和值

Question

每次更改其中一个选择时，我都会尝试返回值的总和。但总和总是错误的:

$('select').change(function () {
 a = 0;
 $('select').each(function () {
    a += parseInt($('option:selected').val(), 10);
 });
 $('h1 span').html(a);
});

http://jsfiddle.net/vAu3E/

Answer 1

$('select').change(function () {
    var a = 0;
    $('select').each(function () {
        a += parseInt(this[this.selectedIndex].value, 10);
    });
    $('h1 span').html(a);
});

JSFiddle