你可以像这样用它的克隆来替换它

var clone = $('#control').clone();

$('#control').replacewith(clone);

但这个克隆与它的价值太，所以你最好喜欢这样

var emtyValue = $('#control').val('');
var clone = emptyValue.clone();

$('#control').replacewith(clone);

什么? 在验证函数中

document.onlyform.upload.value="";

假设upload是名称:

<input type="file" name="upload" id="csv_doc"/>

我使用JSP，不确定这是否有区别…

对我来说是可行的，而且我觉得这样简单多了。

将其设置为异步的，并在完成按钮所需的操作后重置它。

    <!-- Html Markup --->
    <input id="btn" type="file" value="Button" onchange="function()" />

    <script>
    //Function
    function function(e) {

        //input your coding here           

        //Reset
        var controlInput = $("#btn");
        controlInput.replaceWith(controlInput = controlInput.val('').clone(true));
    } 
    </script>

出于明显的安全原因，您不能设置文件输入的值，甚至是空字符串。

你所要做的就是重置字段所在的表单，或者如果你只想重置包含其他字段的表单的文件输入，使用这个:

function reset_field (e) {
    e.wrap('<form>').parent('form').trigger('reset');
    e.unwrap();
}​

这里有一个例子:http://jsfiddle.net/v2SZJ/1/

在IE8中，为了安全起见，他们将文件上传字段设置为只读。查看IE团队的博客文章:

Historically, the HTML File Upload Control () has been the source of a significant number of information disclosure vulnerabilities. To resolve these issues, two changes were made to the behavior of the control. To block attacks that rely on “stealing” keystrokes to surreptitiously trick the user into typing a local file path into the control, the File Path edit box is now read-only. The user must explicitly select a file for upload using the File Browse dialog. Additionally, the “Include local directory path when uploading files” URLAction has been set to "Disable" for the Internet Zone. This change prevents leakage of potentially sensitive local file-system information to the Internet. For instance, rather than submitting the full path C:\users\ericlaw\documents\secret\image.png, Internet Explorer 8 will now submit only the filename image.png.

我被这里的选项困住了。下面是我做的一个有效的方法:

<form>
 <input type="file">
 <button type="reset" id="file_reset" style="display:none">
</form>

你可以使用jQuery来触发重置，代码如下:

$('#file_reset').trigger('click');

（JSFIDDLE： http://jsfiddle.net/eCbd6/）