要底層實現？給你底層C++的偽代碼。
[Exposed=(Window,DedicatedWorker,SharedWorker)]
interface XMLHttpRequestEventTarget : EventTarget {
// event handlers
attribute EventHandler onloadstart;
attribute EventHandler onprogress;
attribute EventHandler onabort;
attribute EventHandler onerror;
attribute EventHandler onload;
attribute EventHandler ontimeout;
attribute EventHandler onloadend;
};
[Exposed=(Window,DedicatedWorker,SharedWorker)]
interface XMLHttpRequestUpload : XMLHttpRequestEventTarget {
};
enum XMLHttpRequestResponseType {
"",
"arraybuffer",
"blob",
"document",
"json",
"text"
};
[Constructor,
Exposed=(Window,DedicatedWorker,SharedWorker)]
interface XMLHttpRequest : XMLHttpRequestEventTarget {
// event handler
attribute EventHandler onreadystatechange;
// states
const unsigned short UNSENT = 0;
const unsigned short OPENED = 1;
const unsigned short HEADERS_RECEIVED = 2;
const unsigned short LOADING = 3;
const unsigned short DONE = 4;
readonly attribute unsigned short readyState;
// request
void open(ByteString method, USVString url);
void open(ByteString method, USVString url, boolean async, optional USVString? username = null, optional USVString? password = null);
void setRequestHeader(ByteString name, ByteString value);
attribute unsigned long timeout;
attribute boolean withCredentials;
[SameObject] readonly attribute XMLHttpRequestUpload upload;
void send(optional (Document or BodyInit)? body = null);
void abort();
// response
readonly attribute USVString responseURL;
readonly attribute unsigned short status;
readonly attribute ByteString statusText;
ByteString? getResponseHeader(ByteString name);
ByteString getAllResponseHeaders();
void overrideMimeType(DOMString mime);
attribute XMLHttpRequestResponseType responseType;
readonly attribute any response;
readonly attribute USVString responseText;
[Exposed=Window] readonly attribute Document? responseXML;
};
