https://developer.mozilla.org/zh-CN/docs/AJAX
https://developer.mozilla.org/zh-CN/docs/AJAX/Getting_Started
https://developer.mozilla.org/zh-CN/docs/Web/API/XMLHttpRequest
https://developer.mozilla.org/zh-CN/docs/Web/API/XMLHttpRequest/Using_XMLHttpRequest
https://developer.mozilla.org/zh-CN/docs/Web/API/GlobalFetch/fetch
https://developer.mozilla.org/zh-CN/docs/Web/API/Worker
https://developer.mozilla.org/zh-CN/docs/Server-sent_events/Using_server-sent_events
new Blob
http://www.javascripture.com/Blob
Creates a new Blob.
The elements of blobParts must be of the types ArrayBuffer, ArrayBufferView, Blob, or String.
If ending is set to 'native', the line endings in the blob will be converted to the system line endings,
such as '\r\n' for Windows or '\n' for Mac.