｛lastModified:1247549551674lastModifiedDate:Tue Jul 14 2009 13:32:31 GMT+0800 (中国标准时间) {}name:"ju.jpg"size:879394type:"image/jpeg"webkitRelativePath:""
｝

var formData = new FormData();formData.append("username", "Groucho");
formData.append("accountnum", 123456); // 数字 123456 会被立即转换成字符串 "123456"// HTML 文件类型input，由用户选择
formData.append("userfile", fileInputElement.files[0]);// JavaScript file-like 对象var content = '<a id="a"><b id="b">hey!</b></a>'; // 新文件的正文...var blob = new Blob([content], { type: "text/xml"});

formData.append("webmasterfile", blob);var request = new XMLHttpRequest();
request.open("POST", "http://foo.com/submitform.php");
request.send(formData);

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

enctype="multipart/form-data"  文件的二进制属性

<style>.anviz-upload-file .image-item{width: 30px;height: 30px;background-image: url(../../img/icon/add.png);background-size: 100% 100%;display: inline-block;position: relative;border-radius: 5px;margin-right: 10px;margin-bottom: 10px;border: solid 1px #e8e8e8;margin-left: 20px;}.anviz-upload-file .image-item .image-close{position: absolute;display: inline-block;right: -6px;top: -6px;width: 20px;height: 20px;text-align: center;line-height: 20px;border-radius: 12px;background-color: #FF5053;color: #f3f3f3;border: solid 1px #FF5053;font-size: 9px;font-weight: 200;z-index: 1;}.anviz-upload-file .image-item input[type="file"]{position: absolute;left: 0px;top: 0px;width: 100%;height: 100%;opacity: 0;cursor: pointer;z-index: 0;}.img-list{width: 100%;height: 105px;padding: 10px 10px;overflow: hidden;border-top: 1px solid #c8c7cc;border-bottom: 1px solid #c8c7cc;background: #fff;margin: 0;display: -webkit-box;display: -ms-flexbox;display: flex;justify-content: flex-start;overflow: scroll;}.img-list li{position: relative;margin-right: 15px;}.img-list li img{width: 85px;height: 85px;}.img-list li span{position: absolute;top: -5px;left: 73px;background: #00a0e8;width: 20px;height: 20px;border-radius: 20px;text-align: center;line-height: 18px;color: #fff;}</style><ul class="mui-table-view mui-grid-view mui-grid-9"><li class="mui-table-view-cell mui-media mui-col-xs-6 mui-col-sm-6 anviz-upload-warp" style="display: flex;padding: 0;"><h5 class="anviz-padded">Attachments</h5><div class="anviz-upload-file"><div class="image-item"><input id="file" type="file" /></div></div></li>
</ul>
<ul id="imgList" class="img-list"></ul>

<script>mui.ready(function(){var myfile = document.getElementById('file');   var List = document.getElementsByClassName('img-list')[0];myfile.onchange = function(){var files = this.files;if(!files)return;       for(var i = 0;i<files.length;i++){                    var oLi = '<li><img src="'+URL.createObjectURL(files[i])+'"><span class="close" οnclick="closeli(this)" >&times;</span></li>';  List.innerHTML+=oLi;          }}});function closeli(obj){var filearr = [];var closes = document.getElementsByClassName('close');[].slice.call(closes).forEach(function(dom,index){if(obj === closes[index]){filearr.splice(index,1);                                    };});obj.parentNode.remove();                  }</script>