axios post请求

URLSearchParams 官方文档

var params = new URLSearchParams()
params.append(key,value)
...
axios.post(API,params).then(res=>{})

伪造表单 FormData 官方文档

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);

  var form = new FormData()
    form.append("title",carousel.title)
    form.append("desc",carousel.desc)
    form.append("pic",carousel.imgurl) 
    return axios.post(API_CreateCarousel,form,null).then(
        res=>res.data
    )