Interface XMLHttpRequest

    Use XMLHttpRequest (XHR) objects to interact with servers. You can retrieve data from a URL without having to do a full page refresh. This enables a Web page to update just part of a page without disrupting what the user is doing.

    MDN Reference

    interface XMLHttpRequest {
        DONE: 4;
        HEADERS_RECEIVED: 2;
        LOADING: 3;
        onabort: ((this: XMLHttpRequest, ev: ProgressEvent<EventTarget>) => any);
        onerror: ((this: XMLHttpRequest, ev: ProgressEvent<EventTarget>) => any);
        onload: ((this: XMLHttpRequest, ev: ProgressEvent<EventTarget>) => any);
        onloadend: ((this: XMLHttpRequest, ev: ProgressEvent<EventTarget>) => any);
        onloadstart: ((this: XMLHttpRequest, ev: ProgressEvent<EventTarget>) => any);
        onprogress: ((this: XMLHttpRequest, ev: ProgressEvent<EventTarget>) => any);
        onreadystatechange: ((this: XMLHttpRequest, ev: Event) => any);
        ontimeout: ((this: XMLHttpRequest, ev: ProgressEvent<EventTarget>) => any);
        OPENED: 1;
        readyState: number;
        response: any;
        responseText: string;
        responseType: XMLHttpRequestResponseType;
        responseURL: string;
        responseXML: Document;
        status: number;
        statusText: string;
        timeout: number;
        UNSENT: 0;
        upload: XMLHttpRequestUpload;
        withCredentials: boolean;
        abort(): void;
        addEventListener<K>(type: K, listener: ((this: XMLHttpRequest, ev: XMLHttpRequestEventMap[K]) => any), options?: boolean | AddEventListenerOptions): void;
        addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
        dispatchEvent(event: Event): boolean;
        getAllResponseHeaders(): string;
        getResponseHeader(name: string): string;
        open(method: string, url: string | URL): void;
        open(method: string, url: string | URL, async: boolean, username?: string, password?: string): void;
        overrideMimeType(mime: string): void;
        removeEventListener<K>(type: K, listener: ((this: XMLHttpRequest, ev: XMLHttpRequestEventMap[K]) => any), options?: boolean | EventListenerOptions): void;
        removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void;
        send(body?: Document | XMLHttpRequestBodyInit): void;
        setRequestHeader(name: string, value: string): void;
    }
    Hierarchy

    Properties

    DONE HEADERS_RECEIVED LOADING onabort onerror onload onloadend onloadstart onprogress onreadystatechange ontimeout OPENED readyState response responseText responseType responseURL responseXML status statusText timeout UNSENT upload withCredentials

    Methods

    abort addEventListener dispatchEvent getAllResponseHeaders getResponseHeader open overrideMimeType removeEventListener send setRequestHeader

    Properties

    ReadonlyDONE

    DONE: 4

    ReadonlyHEADERS_RECEIVED

    HEADERS_RECEIVED: 2

    ReadonlyLOADING

    LOADING: 3

    onabort

    onabort: ((this: XMLHttpRequest, ev: ProgressEvent<EventTarget>) => any)

    onerror

    onerror: ((this: XMLHttpRequest, ev: ProgressEvent<EventTarget>) => any)

    onload

    onload: ((this: XMLHttpRequest, ev: ProgressEvent<EventTarget>) => any)

    onloadend

    onloadend: ((this: XMLHttpRequest, ev: ProgressEvent<EventTarget>) => any)

    onloadstart

    onloadstart: ((this: XMLHttpRequest, ev: ProgressEvent<EventTarget>) => any)

    onprogress

    onprogress: ((this: XMLHttpRequest, ev: ProgressEvent<EventTarget>) => any)

    onreadystatechange

    onreadystatechange: ((this: XMLHttpRequest, ev: Event) => any)

    MDN Reference

    ontimeout

    ontimeout: ((this: XMLHttpRequest, ev: ProgressEvent<EventTarget>) => any)

    ReadonlyOPENED

    OPENED: 1

    ReadonlyreadyState

    readyState: number

    Returns client's state.

    MDN Reference

    Readonlyresponse

    response: any

    Returns the response body.

    MDN Reference

    ReadonlyresponseText

    responseText: string

    Returns response as text.

    Throws an "InvalidStateError" DOMException if responseType is not the empty string or "text".

    MDN Reference

    responseType

    responseType: XMLHttpRequestResponseType

    Returns the response type.

    Can be set to change the response type. Values are: the empty string (default), "arraybuffer", "blob", "document", "json", and "text".

    When set: setting to "document" is ignored if current global object is not a Window object.

    When set: throws an "InvalidStateError" DOMException if state is loading or done.

    When set: throws an "InvalidAccessError" DOMException if the synchronous flag is set and current global object is a Window object.

    MDN Reference

    ReadonlyresponseURL

    responseURL: string

    MDN Reference

    ReadonlyresponseXML

    responseXML: Document

    Returns the response as document.

    Throws an "InvalidStateError" DOMException if responseType is not the empty string or "document".

    MDN Reference

    Readonlystatus

    status: number

    MDN Reference

    ReadonlystatusText

    statusText: string

    MDN Reference

    timeout

    timeout: number

    Can be set to a time in milliseconds. When set to a non-zero value will cause fetching to terminate after the given time has passed. When the time has passed, the request has not yet completed, and this's synchronous flag is unset, a timeout event will then be dispatched, or a "TimeoutError" DOMException will be thrown otherwise (for the send() method).

    When set: throws an "InvalidAccessError" DOMException if the synchronous flag is set and current global object is a Window object.

    MDN Reference

    ReadonlyUNSENT

    UNSENT: 0

    Readonlyupload

    upload: XMLHttpRequestUpload

    Returns the associated XMLHttpRequestUpload object. It can be used to gather transmission information when data is transferred to a server.

    MDN Reference

    withCredentials

    withCredentials: boolean

    True when credentials are to be included in a cross-origin request. False when they are to be excluded in a cross-origin request and when cookies are to be ignored in its response. Initially false.

    When set: throws an "InvalidStateError" DOMException if state is not unsent or opened, or if the send() flag is set.

    MDN Reference

    Methods

    abort

    • abort(): void

    • Cancels any network activity.

      MDN Reference

      Returns void

    addEventListener

    • addEventListener<K>(type, listener, options?): void

    • Appends an event listener for events whose type attribute value is type. The callback argument sets the callback that will be invoked when the event is dispatched.

      The options argument sets listener-specific options. For compatibility this can be a boolean, in which case the method behaves exactly as if the value was specified as options's capture.

      When set to true, options's capture prevents callback from being invoked when the event's eventPhase attribute value is BUBBLING_PHASE. When false (or not present), callback will not be invoked when event's eventPhase attribute value is CAPTURING_PHASE. Either way, callback will be invoked if event's eventPhase attribute value is AT_TARGET.

      When set to true, options's passive indicates that the callback will not cancel the event by invoking preventDefault(). This is used to enable performance optimizations described in § 2.8 Observing event listeners.

      When set to true, options's once indicates that the callback will only be invoked once after which the event listener will be removed.

      If an AbortSignal is passed for options's signal, then the event listener will be removed when signal is aborted.

      The event listener is appended to target's event listener list and is not appended if it has the same type, callback, and capture.

      MDN Reference

      Type Parameters

      Parameters

      Returns void

    • addEventListener(type, listener, options?): void

    • Appends an event listener for events whose type attribute value is type. The callback argument sets the callback that will be invoked when the event is dispatched.

      The options argument sets listener-specific options. For compatibility this can be a boolean, in which case the method behaves exactly as if the value was specified as options's capture.

      When set to true, options's capture prevents callback from being invoked when the event's eventPhase attribute value is BUBBLING_PHASE. When false (or not present), callback will not be invoked when event's eventPhase attribute value is CAPTURING_PHASE. Either way, callback will be invoked if event's eventPhase attribute value is AT_TARGET.

      When set to true, options's passive indicates that the callback will not cancel the event by invoking preventDefault(). This is used to enable performance optimizations described in § 2.8 Observing event listeners.

      When set to true, options's once indicates that the callback will only be invoked once after which the event listener will be removed.

      If an AbortSignal is passed for options's signal, then the event listener will be removed when signal is aborted.

      The event listener is appended to target's event listener list and is not appended if it has the same type, callback, and capture.

      MDN Reference

      Parameters

      Returns void

    dispatchEvent

    • dispatchEvent(event): boolean

    • Dispatches a synthetic event event to target and returns true if either event's cancelable attribute value is false or its preventDefault() method was not invoked, and false otherwise.

      MDN Reference

      Parameters

      Returns boolean

    getAllResponseHeaders

    getResponseHeader

    • getResponseHeader(name): string

    • MDN Reference

      Parameters

      • name: string

      Returns string

    open

    • open(method, url): void

    • Sets the request method, request URL, and synchronous flag.

      Throws a "SyntaxError" DOMException if either method is not a valid method or url cannot be parsed.

      Throws a "SecurityError" DOMException if method is a case-insensitive match for CONNECT, TRACE, or TRACK.

      Throws an "InvalidAccessError" DOMException if async is false, current global object is a Window object, and the timeout attribute is not zero or the responseType attribute is not the empty string.

      MDN Reference

      Parameters

      • method: string
      • url: string | URL

      Returns void

    • open(method, url, async, username?, password?): void

    • Parameters

      • method: string
      • url: string | URL
      • async: boolean
      • Optionalusername: string
      • Optionalpassword: string

      Returns void

    overrideMimeType

    • overrideMimeType(mime): void

    • Acts as if the Content-Type header value for a response is mime. (It does not change the header.)

      Throws an "InvalidStateError" DOMException if state is loading or done.

      MDN Reference

      Parameters

      • mime: string

      Returns void

    removeEventListener

    send

    • send(body?): void

    • Initiates the request. The body argument provides the request body, if any, and is ignored if the request method is GET or HEAD.

      Throws an "InvalidStateError" DOMException if either state is not opened or the send() flag is set.

      MDN Reference

      Parameters

      Returns void

    setRequestHeader

    • setRequestHeader(name, value): void

    • Combines a header in author request headers.

      Throws an "InvalidStateError" DOMException if either state is not opened or the send() flag is set.

      Throws a "SyntaxError" DOMException if name is not a header name or if value is not a header value.

      MDN Reference

      Parameters

      • name: string
      • value: string

      Returns void

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