get方法

var xhr = new XMLHttpRequest();
var formData = new FormData();
xhr.open('get','url');  //url填写后台的接口地址，如果是post，在formData append参数（参考原文地址）
xhr.setRequestHeader("access-token", sessionStorage.getItem('access-token'));
xhr.responseType = 'blob';
xhr.onload = function (e) {
    if (this.status == 200) {
        var blob = this.response;
        var filename = "设备导出.xls";
        console.log(this.response)
         if (window.navigator.msSaveOrOpenBlob) {
            navigator.msSaveBlob(blob, filename);
        } else {
          var a = document.createElement('a');
         var url = createObjectURL(blob);
         a.href = url;
         a.download = filename;
         document.body.appendChild(a);
         a.click();
         window.URL.revokeObjectURL(url);
        }

    }
};
xhr.send(formData);