axios+Vue上传文件显示进度

<div id="app">
<h4>上传文件：</h4>
<p class="input-zone">
<span v-if="filename">{{filename}}</span>
<span v-else>+请选择文件上传+</span> <input type="file" name="file" value="" placeholder="请选择文件" @change="upload" multiple="multiple" />
</p> <p>上传进度：</p>
<div class="progress-wrapper">
<div class="progress-progress" :style="uploadStyle"></div>
<div class="progress-rate">{{(uploadRate*100).toFixed(2)}}%</div>
</div> </div>

.input-zone { width: 500px; color: blue; font-size: 14px; position: relative; }
.input-zone input[type='file'] { opacity: 0; width: 100%; height: 100%; position: absolute; left: 0; top: 0; z-index: 2; }
.progress-wrapper { position: relative; height: 50px; border-radius: 5px; background-color: lightgrey; }
.progress-wrapper .progress-progress { position: absolute; left: 0; top: 0; height: 100%; width: 0%; border-radius: 5px; background-color: darkturquoise; z-index: 1; }
.progress-wrapper .progress-rate { position: relative; text-align: center; font-size: 14px; line-height: 50px; height: 100%; z-index:2;}

var app = new Vue({
el: "#app",
data: {
uploadRate: 0,
filename: '',
uploadStyle: {
width: '0%'
}
},
methods: {
upload: function (e) {
var vm = this;
var formData = new FormData();
formData.append("name", "Alax");
for (var i = 0; i < e.target.files.length; i++) {
var file = e.target.files[i]; //取第1个文件
formData.append("file", file);
vm.filename = file.name;
console.log(file);
} var config = {
headers: { 'Content-Type': 'multipart/form-data' },
onUploadProgress: function (e) {
console.log("进度：");
console.log(e);
//属性lengthComputable主要表明总共需要完成的工作量和已经完成的工作是否可以被测量
//如果lengthComputable为false，就获取不到e.total和e.loaded
if (e.lengthComputable) {
var rate = vm.uploadRate = e.loaded / e.total; //已上传的比例
if (rate < 1) {
//这里的进度只能表明文件已经上传到后台，但是后台有没有处理完还不知道
//因此不能直接显示为100%，不然用户会误以为已经上传完毕，关掉浏览器的话就可能导致上传失败
//等响应回来时，再将进度设为100%
vm.uploadRate = rate;
vm.uploadStyle.width = (rate *100).toFixed(2)+ '%';
}
}
}
}; axios.post("/ajaxPage/VueUpload.aspx?method=upload", formData, config)
.then(function (data) {
console.log(data);
var json = data.data; //后台实际返回的结果
if (json.result) {
vm.uploadRate = 1;
vm.uploadStyle.width = '100.00%';
} else {
alert(json.msg);
}
})
.catch(function (err) {
console.log(err);
});
}
}
})