Blob构造函数下载文本内容

点击a标签下载

<a download="hello.txt" href='#' id="link">Download</a>

<script>
   let blob = new Blob(["Hello, world!"], {type: 'text/plain'}); 
   link.href = URL.createObjectURL(blob);
</script>

动态创建a标签下载

let link = document.createElement('a');
link.download = 'hello.txt';

let blob = new Blob(['Hello, world!'], {type: 'text/plain'});

let reader = new FileReader();
reader.readAsDataURL(blob); // converts the blob to base64 and calls onload

reader.onload = function() {
    link.href = reader.result; // data url
    link.click();
};

let link = document.createElement('a');
link.download = 'hello.txt';

let blob = new Blob(['Hello, world!'], {type: 'text/plain'});

link.href = URL.createObjectURL(blob);

link.click();

URL.revokeObjectURL(link.href);

来源：https://javascript.info/blob