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abort method (XMLHttpRequest)

Browser support:
Interrupts the current HTTP request.
This function can be used for asynchronous operations. When a request is aborted, the onreadystatechange event handler is not called and the readyState property is set to zero.


object.abort ( );
You can find the related objects in the Supported by objects section below.

Return value:

This method has no return value.

Example HTML code 1:

This example shows how to cancel an HTTP request.
    <script type="text/javascript" src="ajax.js"></script>
    <script type="text/javascript">
        var httpRequest = null;

        function SendRequest () {
            if (!httpRequest) {
                httpRequest = CreateHTTPRequestObject ();   // defined in ajax.js
            if (httpRequest) {          
                    // The requested file must be in the same domain that the page is served from.
                var url = "large.xml";

       ("GET", url, true);    // async
                httpRequest.onreadystatechange = OnStateChange;
                httpRequest.send (null);

                var abortButton = document.getElementById ("abortButton");
                abortButton.disabled = false;

        function OnStateChange () {
            var output = document.getElementById ("output");
            switch (httpRequest.readyState) {
            case 1:
                output.innerHTML += "The request is opened, but the send method has not been called yet.<br />";
            case 2:
                output.innerHTML += "The request is sent but no data has been received yet.<br />";
            case 3:
                output.innerHTML += "A part of the data has been received.<br />";
            case 4:
                var abortButton = document.getElementById ("abortButton");
                if (!abortButton.disabled) {
                    if (IsRequestSuccessful (httpRequest)) {    // defined in ajax.js
                        output.innerHTML += "All the data has been received.<br/>";
                    else {
                        output.innerHTML += "<span style='color:red'>Operation failed!</span><br/>";
                    abortButton.disabled = true;

        function AbortRequest () {
            var abortButton = document.getElementById ("abortButton");
            abortButton.disabled = true;

            var output = document.getElementById ("output");
            output.innerHTML += "<span style='color:red'>Operation is aborted!</span><br/>";

            httpRequest.abort ();        // aborts the request

    <button onclick="SendRequest ()">Send request</button>
    <div id="output" style="width:420px; height:200px; overflow:auto; border:1px solid #000000; background-color:#f5e4b1;"></div>
    <button id="abortButton" onclick="AbortRequest ()" disabled="disabled">Abort request</button>
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