define([

"../core",
"../var/support",
"../ajax"

], function( jQuery, support ) {

jQuery.ajaxSettings.xhr = function() {

try {
        return new XMLHttpRequest();
} catch( e ) {}

};

var xhrId = 0,

xhrCallbacks = {},
xhrSuccessStatus = {
        // file protocol always yields status code 0, assume 200
        0: 200,
        // Support: IE9
        // #1450: sometimes IE returns 1223 when it should be 204
        1223: 204
},
xhrSupported = jQuery.ajaxSettings.xhr();

// Support: IE9 // Open requests must be manually aborted on unload (#5280) // See support.microsoft.com/kb/2856746 for more info if ( window.attachEvent ) {

window.attachEvent( "onunload", function() {
        for ( var key in xhrCallbacks ) {
                xhrCallbacks[ key ]();
        }
});

}

support.cors = !!xhrSupported && ( “withCredentials” in xhrSupported ); support.ajax = xhrSupported = !!xhrSupported;

jQuery.ajaxTransport(function( options ) {

var callback;

// Cross domain only allowed if supported through XMLHttpRequest
if ( support.cors || xhrSupported && !options.crossDomain ) {
        return {
                send: function( headers, complete ) {
                        var i,
                                xhr = options.xhr(),
                                id = ++xhrId;

                        xhr.open( options.type, options.url, options.async, options.username, options.password );

                        // Apply custom fields if provided
                        if ( options.xhrFields ) {
                                for ( i in options.xhrFields ) {
                                        xhr[ i ] = options.xhrFields[ i ];
                                }
                        }

                        // Override mime type if needed
                        if ( options.mimeType && xhr.overrideMimeType ) {
                                xhr.overrideMimeType( options.mimeType );
                        }

                        // X-Requested-With header
                        // For cross-domain requests, seeing as conditions for a preflight are
                        // akin to a jigsaw puzzle, we simply never set it to be sure.
                        // (it can always be set on a per-request basis or even using ajaxSetup)
                        // For same-domain requests, won't change header if already provided.
                        if ( !options.crossDomain && !headers["X-Requested-With"] ) {
                                headers["X-Requested-With"] = "XMLHttpRequest";
                        }

                        // Set headers
                        for ( i in headers ) {
                                xhr.setRequestHeader( i, headers[ i ] );
                        }

                        // Callback
                        callback = function( type ) {
                                return function() {
                                        if ( callback ) {
                                                delete xhrCallbacks[ id ];
                                                callback = xhr.onload = xhr.onerror = null;

                                                if ( type === "abort" ) {
                                                        xhr.abort();
                                                } else if ( type === "error" ) {
                                                        complete(
                                                                // file: protocol always yields status 0; see #8605, #14207
                                                                xhr.status,
                                                                xhr.statusText
                                                        );
                                                } else {
                                                        complete(
                                                                xhrSuccessStatus[ xhr.status ] || xhr.status,
                                                                xhr.statusText,
                                                                // Support: IE9
                                                                // Accessing binary-data responseText throws an exception
                                                                // (#11426)
                                                                typeof xhr.responseText === "string" ? {
                                                                        text: xhr.responseText
                                                                } : undefined,
                                                                xhr.getAllResponseHeaders()
                                                        );
                                                }
                                        }
                                };
                        };

                        // Listen to events
                        xhr.onload = callback();
                        xhr.onerror = callback("error");

                        // Create the abort callback
                        callback = xhrCallbacks[ id ] = callback("abort");

                        try {
                                // Do send the request (this may raise an exception)
                                xhr.send( options.hasContent && options.data || null );
                        } catch ( e ) {
                                // #14683: Only rethrow if this hasn't been notified as an error yet
                                if ( callback ) {
                                        throw e;
                                }
                        }
                },

                abort: function() {
                        if ( callback ) {
                                callback();
                        }
                }
        };
}

});

});