嗨，我正在尝试使用此代码发送带有xmlhttprequest的文件。

var url= "http://localhost:80/....";

$(document).ready(function(){

document.getElementById('upload').addEventListener('change', function(e) {

var file = this.files[0];

var xhr = new XMLHttpRequest();

xhr.file = file; // not necessary if you create scopes like this

xhr.addEventListener('progress', function(e) {

var done = e.position || e.loaded, total = e.totalSize || e.total;

console.log('xhr progress: ' + (Math.floor(done/total*1000)/10) + '%');

}, false);

if ( xhr.upload ) {

xhr.upload.onprogress = function(e) {

var done = e.position || e.loaded, total = e.totalSize || e.total;

console.log('xhr.upload progress: ' + done + ' / ' + total + ' = ' + (Math.floor(done/total*1000)/10) + '%');

};

}

xhr.onreadystatechange = function(e) {

if ( 4 == this.readyState ) {

console.log(['xhr upload complete', e]);

}

};

xhr.open('post', url, true);

xhr.setRequestHeader("Content-Type","multipart/form-data");

xhr.send(file);

}, false);

});

但我收到此错误：请求被拒绝，因为未找到多部分边界，请帮助我。