使用val()不适合我。我必须在任何地方使用.attr()。此外，我有不同类型的输入，在复选框和选择菜单的情况下必须非常明确。

更新文本框

$('#model_name').attr('value',nameVal);

更新文件输入旁边的图像

$('#img-avatar').attr('src', avatarThumbUrl);

更新布尔

if (isActive) {
    $('#model_active').attr('checked',"checked");
} else {
    $('#model_active').attr('checked', null) ;
}

更新选择(包含数字或字符串)

$('#model_framerate').children().each(function(i, el){
    var v = $(el).val();
    if (v === String(framerateVal)) { 
        $(el).attr('selected','selected');
    } else {
        $(el).attr('selected',null);
    }
}

我也有同样的问题，我找到了问题所在。我把HTML定义为

<form action="url" method="post">
    <input type="hidden" id="email" />
<form>
<script>
    function onsomeevent()
    {
       $("#email").val("a@a.com");
    }
</script>

在服务器上读取表单值总是导致电子邮件为空。在绞尽脑汁(和无数次搜索)之后，我意识到错误在于没有正确定义表单/输入。在修改输入时(如下所示)，它就像一个咒语一样有效

<input type="hidden" id="email" name="email" />

添加到这个线程，以防其他人有同样的问题。

最后，我找到了一个解决方案，很简单:

document.getElementById("texens").value = "tinkumaster";

效果非常好。不知道为什么jQuery没有退回到这一步。

$('input[name=hidden_field_name]').val('newVal');

为我工作，其实两者都不是

$('input[id=hidden_field_id]').val('newVal');

nor

$('#hidden_field_id').val('newVal');

did.

:text对于type值为hidden的输入将失败。只使用以下语句也会更有效率:

$("#texens").val("tinkumaster");

ID属性在网页上应该是唯一的，确保你的ID属性是唯一的，因为这可能会导致你遇到的任何问题，指定一个更复杂的选择器只会减慢速度，看起来不那么整洁。

http://jsbin.com/elovo/edit上的示例，使用http://jsbin.com/elovo/2/edit上的示例代码

Actually, this is an ongoing problem. While Andy is right about the downloaded source, .val(...) and .attr('value',...) don't seem to actually modify the html. I think this is a javascript problem and not a jquery problem. If you had used firebug even you would have had the same question. While it seems that if you submit the form with the modified values it will go through, the html does not change. I ran into this issue trying to create a print preview of the modified form (doing [form].html()) it copies everything okay, including all changes except values changes. Thus, my modal print preview is somewhat useless... my workaround may have to be to 'build' a hidden form containing the values they have added, or generate the preview independently and make each modification the user makes also modify the preview. Both are inoptimal, but unless someone figures out why the value-setting behavior does not change the html (in the DOM i'm assuming) it will have to do.