如何异步上传文件？ - How can I upload files asynchronously?

问题：

I would like to upload a file asynchronously with jQuery. 我想用jQuery异步上传文件。 This is my HTML: 这是个人HTML：

<span>File</span>
<input type="file" id="file" name="file" size="10"/>
<input id="uploadbutton" type="button" value="Upload"/>

And here my jQuery code: 这是个人jQuery代码：

$(document).ready(function () {
    $("#uploadbutton").click(function () {
        var filename = $("#file").val();

        $.ajax({
            type: "POST",
            url: "addFile.do",
            enctype: 'multipart/form-data',
            data: {
                file: filename
            },
            success: function () {
                alert("Data Uploaded: ");
            }
        });
    });
});

Instead of the file being uploaded, I am only getting the filename. 我只获取文件名，而不是上传文件。 What can I do to fix this problem? 我该怎么作才能解决此问题？

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解决方案：

参考一： https://stackoom.com/question/hEz/如何异步上传文件
参考二： https://oldbug.net/q/hEz/How-can-I-upload-files-asynchronously