您可以在anchor元素中使用download attr，这将强制下载，并且您不需要重新创建另一个Blob.

You can use the download attr in anchor element, that force the download and you dont need to reate another blob.

但是您需要注意有关浏览器的支持，请在此处查看所有接受download attr的浏览器:我可以使用

But you need to pay attentio about browser support, see here all the browsers that accept the downloadattr: Can I Use

var blob1 = new Blob(["Hello world!"], { type: "text/plain" });
url = window.URL.createObjectURL(blob1);

var a = document.createElement("a");
document.body.appendChild(a);
a.style = "display: none";
a.href = url;
a.setAttribute("download","Any name");
a.click();
window.URL.revokeObjectURL(url);

要从Blob中读取内容，您可以像这样使用FileReader:

And to read the content from a Blob you can use FileReader like this:

var myBlob = new Blob(["Hello"], {type : "text/plain"});
var myReader = new FileReader();
//handler executed once reading(blob content referenced to a variable) from blob is finished. 
myReader.addEventListener("loadend", function(e){
    document.getElementById("text").innerHTML = e.srcElement.result;//prints a string
});
//start the reading process.
myReader.readAsText(myBlob);

<p id="text"></p>