JavaScript: download系

Posted at 2024-11-17

URL.createObjectURLとURL.revokeObjectURLを組み合わせたdownloadの成功例と失敗例

自動

成功

let a=document.createElement("a");
a.download="a";
a.href=URL.createObjectURL(new Blob(["text"]));
a.click();
URL.revokeObjectURL(a.href)

失敗

let a=document.createElement("a");
a.download="a";
a.click(URL.revokeObjectURL(a.href=URL.createObjectURL(new Blob(["text"]))))

成功

let a=document.createElement("a");
URL.revokeObjectURL(a.href=URL.createObjectURL(new Blob(["text"])),a.click(a.download="a"))
//2回目は失敗
a.click()

失敗

<a id=a download>DL</a><script>
a.onclick=()=>{
	a.href=URL.createObjectURL(new Blob(["text"]));
	URL.revokeObjectURL(a.href)
}
</script>

失敗

<a id=a download>DL</a><script>
a.onclick=()=>URL.revokeObjectURL(a.href=URL.createObjectURL(new Blob(["text"])))
</script>