解决：js 根据图片链接（image url）下载，有的打开预览，有的下载

/**      *  ### 适合预览操作的 Blob 类型，需要将链接地址字符内容转变成blob地址           - image/png           - image/jpeg           - image/gif           - audio/mpeg           - audio/ogg           - audio/wav           - video/mp4           - video/ogg         ### 适合下载操作的 Blob 类型           - text/plain           - text/csv           - application/pdf           - application/json           - application/xml           - application/zip           - application/octet-stream      */     async function downloadImg(url) {       try {         const res = await fetch(url);         if (!res.ok) {           throw new Error("fetch network response was not ok");         }         const blob = await res.blob();         if (           blob.type.includes("image") ||           blob.type.includes("audio") ||           blob.type.includes("video")         ) {           const a = document.createElement("a");           a.href = URL.createObjectURL(blob);           a.download = "";           document.body.appendChild(a);           a.click();         } else {           window.open(url);         }       } catch (error) {         //有些图片url请求本身就出现了跨域等问题，目前纯前端本人还无解，只能直接open         console.log("catcherror", err);         window.open(url);       }     }