您可以使用
fetch()，
Response.body.getReader()它返回一个
ReadableStream，
TextDeprer()，
Blob()，
URL.createObjectURL()。
注意，在设备具有有限的
RAM或较低的可用磁盘空间，点击后
Save在
Save File对话框4分钟二十秒
4:20经过的前
SaveFile对话关闭，随后是附加的一分钟，30秒
1:30的前
.crdownload延伸部，从在文件管理器GUI的文件中删除。在第一个
4:20将文件下载到文件系统并且
SaveFile可以看到对话框的时期，鼠标指针是可移动的，尽管UI暂时不响应单击或尝试更改选项卡。当
SaveFile对话框关闭并且文件仍在下载到文件系统时，扩展后
.crdownload的UI会恢复正常功能。
在上述过程结束时，文件已成功下载到本地文件系统，总大小为
189.8 MB (189,778,220 bytes)。
<!DOCTYPE html><html><head> <style> pre { color:navy; background-color:#eee; padding:2px; } </style></head><body> <button>Request File</button><br> <progress min="0" max="189778220" value="0"></progress> <output></output> <br><br> <label></label> <script> var url = "https://raw.githubusercontent.com/zemirco/sf-city-lots-json/master/citylots.json"; var button = document.querySelector("button"); var progress = document.querySelector("progress"); var label = document.querySelector("label"); var output = document.querySelector("output"); var request = (url) => { label.innerHTML = `Requesting <pre>${url}</pre> at ${new Date()}.<br><br>`; return fetch(url) .then(response => response.body.getReader()) .then(reader => { var deprer = new TextDeprer(); var json = ""; label.innerHTML += `Request successful.<br><br>Reading request body at ${new Date()}.<br><br>`; return reader.read().then(function processData(result) { if (result.done) { // do stuff when `reader` is `closed` return reader.closed.then(function() { // return `json` string return json; }); }; json += deprer.depre(result.value); output.innerHTML = ` ${json.length} of ${progress.max} bytes read`; progress.value = json.length; return reader.read().then(processData) }) .then(function(data) { var message = `Reading of <pre>${url}</pre> complete at ${new Date()}. <br><br>` + `${data.length} total bytes read. ` + `Please allow up to 4 minutes for file to download ` + `to filesystem after clicking <pre>Save</pre>.<br><br>`; label.innerHTML += message; var blob = new Blob([data], { type: "application/json" }); var file = URL.createObjectURL(blob); var a = document.createElement("a"); a.download = "citylots.json"; a.href = file; document.body.appendChild(a); a.click(); var closeBlob = (e) => { window.removeEventListener("focus", closeBlob); blob.close(); URL.revokeObjectURL(file); }; window.addEventListener("focus", closeBlob); return message.replace(/<[^>]*>/g, ""); }) .catch(function(err) { console.log("err", err) }) }); } var handleRequest = (e) => { button.setAttribute("disabled", "disabled"); request(url).then(function(message) { console.log(message); button.removeAttribute("disabled"); }) }; button.addEventListener("click", handleRequest); </script></body></html>plnkr
https://plnkr.co/edit/gewixzHZSKRXquZ2OVF2?p=preview
