通过jQuery Ajax使用FormData对象上传文件

<form id="uploadForm" enctype="multipart/form-data">
    <input id="file" type="file" name="file"/>
    <button id="upload" type="button">upload</button>
</form>

$.ajax({
    url: '/upload',
    type: 'POST',
    cache: false,
    data: new FormData($('#uploadForm')[0]),
    processData: false,
    contentType: false
}).done(function(res) {}).fail(function(res) {});