iframe实现跨域和修改标题

const base64 = window.URL.createObjectURL(res.data);
const iframe = `<iframe width = '100%' height = '100%' src=${base64} id='iframeTitle'></iframe>`;
const x = window.open();
if (x) {
    x.document.title = '预览';
}
x?.document.close();