JS使用a標籤下載文件

Dowload(url, fileName) {
      let xmlResquest = new XMLHttpRequest();
      xmlResquest.open('GET', url, true);
      xmlResquest.setRequestHeader('Content-type', 'application/json');
      xmlResquest.setRequestHeader(
        'Authorization',
        this.$store.getters.getToken()
      );

      xmlResquest.responseType = 'blob';
      xmlResquest.onload = function (oEvent) {
        if (xmlResquest.status != 200) {
          this.$message({
            type: 'error',
            message: '下載文件出錯了..'
          });
          return;
        }

        const downloadLink = document.createElement('a');
        let content = xmlResquest.response;
        let blob = new Blob([content]);
        downloadLink.href = URL.createObjectURL(blob);;
        downloadLink.setAttribute('download', fileName);
        document.body.appendChild(downloadLink);
        downloadLink.click();
        document.body.removeChild(downloadLink);
      };
      xmlResquest.send();
    }