js下载音频

          downloadAudio(item) {
            const content = item.content.replace('http:','https:');
            let ajax = new XMLHttpRequest();
            ajax.open('GET', content, true);
            ajax.responseType = 'blob';
            //ajx.withCredentials = true;//如果跨域
            ajax.onload = function (oEvent) {
              let response = ajax.response;
              let a = document.createElement('a');
              a.download = content.includes('.amr') ? +new Date() + '.amr' : +new Date() + '.mp3';
              a.style.display = 'none';
              let blob = new Blob([response]);
              a.href = URL.createObjectURL(blob);
              document.body.appendChild(a);
              a.click();
              document.body.removeChild(a);
            };
            ajax.send();
          },