/*Copyright (c) 2007, Yahoo! Inc. All rights reserved.Code licensed under the BSD License:http://developer.yahoo.net/yui/license.txtversion: 2.3.0*//** * The Connection Manager provides a simplified interface to the XMLHttpRequest * object.  It handles cross-browser instantiantion of XMLHttpRequest, negotiates the * interactive states and server response, returning the results to a pre-defined * callback you create. * * @namespace YAHOO.util * @module connection * @requires yahoo * @requires event *//** * The Connection Manager singleton provides methods for creating and managing * asynchronous transactions. * * @class Connect */YAHOO.util.Connect ={  /**   * @description Array of MSFT ActiveX ids for XMLHttpRequest.   * @property _msxml_progid   * @private   * @static   * @type array   */	_msxml_progid:[		'MSXML2.XMLHTTP.3.0',		'MSXML2.XMLHTTP',		'Microsoft.XMLHTTP'		],  /**   * @description Object literal of HTTP header(s)   * @property _http_header   * @private   * @static   * @type object   */	_http_headers:{},  /**   * @description Determines if HTTP headers are set.   * @property _has_http_headers   * @private   * @static   * @type boolean   */	_has_http_headers:false, /**  * @description Determines if a default header of  * Content-Type of 'application/x-www-form-urlencoded'  * will be added to any client HTTP headers sent for POST  * transactions.  * @property _use_default_post_header  * @private  * @static  * @type boolean  */    _use_default_post_header:true, /**  * @description Determines if a default header of  * Content-Type of 'application/x-www-form-urlencoded'  * will be added to client HTTP headers sent for POST  * transactions.  * @property _default_post_header  * @private  * @static  * @type boolean  */    _default_post_header:'application/x-www-form-urlencoded; charset=UTF-8', /**  * @description Determines if a default header of  * 'X-Requested-With: XMLHttpRequest'  * will be added to each transaction.  * @property _use_default_xhr_header  * @private  * @static  * @type boolean  */    _use_default_xhr_header:true, /**  * @description The default header value for the label  * "X-Requested-With".  This is sent with each  * transaction, by default, to identify the  * request as being made by YUI Connection Manager.  * @property _default_xhr_header  * @private  * @static  * @type boolean  */    _default_xhr_header:'XMLHttpRequest', /**  * @description Determines if custom, default headers  * are set for each transaction.  * @property _has_default_header  * @private  * @static  * @type boolean  */    _has_default_headers:true, /**  * @description Determines if custom, default headers  * are set for each transaction.  * @property _has_default_header  * @private  * @static  * @type boolean  */    _default_headers:{}, /**  * @description Property modified by setForm() to determine if the data  * should be submitted as an HTML form.  * @property _isFormSubmit  * @private  * @static  * @type boolean  */    _isFormSubmit:false, /**  * @description Property modified by setForm() to determine if a file(s)  * upload is expected.  * @property _isFileUpload  * @private  * @static  * @type boolean  */    _isFileUpload:false, /**  * @description Property modified by setForm() to set a reference to the HTML  * form node if the desired action is file upload.  * @property _formNode  * @private  * @static  * @type object  */    _formNode:null, /**  * @description Property modified by setForm() to set the HTML form data  * for each transaction.  * @property _sFormData  * @private  * @static  * @type string  */    _sFormData:null, /**  * @description Collection of polling references to the polling mechanism in handleReadyState.  * @property _poll  * @private  * @static  * @type object  */    _poll:{}, /**  * @description Queue of timeout values for each transaction callback with a defined timeout value.  * @property _timeOut  * @private  * @static  * @type object  */    _timeOut:{},  /**   * @description The polling frequency, in milliseconds, for HandleReadyState.   * when attempting to determine a transaction's XHR readyState.   * The default is 50 milliseconds.   * @property _polling_interval   * @private   * @static   * @type int   */     _polling_interval:50,  /**   * @description A transaction counter that increments the transaction id for each transaction.   * @property _transaction_id   * @private   * @static   * @type int   */     _transaction_id:0,  /**   * @description Tracks the name-value pair of the "clicked" submit button if multiple submit   * buttons are present in an HTML form; and, if YAHOO.util.Event is available.   * @property _submitElementValue   * @private   * @static   * @type string   */	 _submitElementValue:null,  /**   * @description Determines whether YAHOO.util.Event is available and returns true or false.   * If true, an event listener is bound at the document level to trap click events that   * resolve to a target type of "Submit".  This listener will enable setForm() to determine   * the clicked "Submit" value in a multi-Submit button, HTML form.   * @property _hasSubmitListener   * @private   * @static   */	 _hasSubmitListener:(function()	 {		if(YAHOO.util.Event){			YAHOO.util.Event.addListener(				document,				'click',				function(e){					var obj = YAHOO.util.Event.getTarget(e);					if(obj.type == 'submit'){						YAHOO.util.Connect._submitElementValue = encodeURIComponent(obj.name) + "=" + encodeURIComponent(obj.value);					}				});			return true;	    }	    return false;	 })(),  /**   * @description Custom event that fires at the start of a transaction   * @property startEvent   * @private   * @static   * @type CustomEvent   */	startEvent: new YAHOO.util.CustomEvent('start'),  /**   * @description Custom event that fires when a transaction response has completed.   * @property completeEvent   * @private   * @static   * @type CustomEvent   */	completeEvent: new YAHOO.util.CustomEvent('complete'),  /**   * @description Custom event that fires when handleTransactionResponse() determines a   * response in the HTTP 2xx range.   * @property successEvent   * @private   * @static   * @type CustomEvent   */	successEvent: new YAHOO.util.CustomEvent('success'),  /**   * @description Custom event that fires when handleTransactionResponse() determines a   * response in the HTTP 4xx/5xx range.   * @property failureEvent   * @private   * @static   * @type CustomEvent   */	failureEvent: new YAHOO.util.CustomEvent('failure'),  /**   * @description Custom event that fires when handleTransactionResponse() determines a   * response in the HTTP 4xx/5xx range.   * @property failureEvent   * @private   * @static   * @type CustomEvent   */	uploadEvent: new YAHOO.util.CustomEvent('upload'),  /**   * @description Custom event that fires when a transaction is successfully aborted.   * @property abortEvent   * @private   * @static   * @type CustomEvent   */	abortEvent: new YAHOO.util.CustomEvent('abort'),  /**   * @description A reference table that maps callback custom events members to its specific   * event name.   * @property _customEvents   * @private   * @static   * @type object   */	_customEvents:	{		onStart:['startEvent', 'start'],		onComplete:['completeEvent', 'complete'],		onSuccess:['successEvent', 'success'],		onFailure:['failureEvent', 'failure'],		onUpload:['uploadEvent', 'upload'],		onAbort:['abortEvent', 'abort']	},  /**   * @description Member to add an ActiveX id to the existing xml_progid array.   * In the event(unlikely) a new ActiveX id is introduced, it can be added   * without internal code modifications.   * @method setProgId   * @public   * @static   * @param {string} id The ActiveX id to be added to initialize the XHR object.   * @return void   */	setProgId:function(id)	{		this._msxml_progid.unshift(id);		YAHOO.log('ActiveX Program Id  ' + id + ' added to _msxml_progid.', 'info', 'Connection');	},  /**   * @description Member to enable or disable the default POST header.   * @method setDefaultPostHeader   * @public   * @static   * @param {boolean} b Set and use default header - true or false .   * @return void   */	setDefaultPostHeader:function(b)	{		this._use_default_post_header = b;		YAHOO.log('Use default POST header set to  ' + b, 'info', 'Connection');	},  /**   * @description Member to enable or disable the default POST header.   * @method setDefaultXhrHeader   * @public   * @static   * @param {boolean} b Set and use default header - true or false .   * @return void   */	setDefaultXhrHeader:function(b)	{		this._use_default_xhr_header = b;		YAHOO.log('Use default transaction header set to  ' + b, 'info', 'Connection');	},  /**   * @description Member to modify the default polling interval.   * @method setPollingInterval   * @public   * @static   * @param {int} i The polling interval in milliseconds.   * @return void   */	setPollingInterval:function(i)	{		if(typeof i == 'number' && isFinite(i)){			this._polling_interval = i;			YAHOO.log('Default polling interval set to ' + i +'ms', 'info', 'Connection');		}	},  /**   * @description Instantiates a XMLHttpRequest object and returns an object with two properties:   * the XMLHttpRequest instance and the transaction id.   * @method createXhrObject   * @private   * @static   * @param {int} transactionId Property containing the transaction id for this transaction.   * @return object   */	createXhrObject:function(transactionId)	{		var obj,http;		try		{			// Instantiates XMLHttpRequest in non-IE browsers and assigns to http.			http = new XMLHttpRequest();			//  Object literal with http and tId properties			obj = { conn:http, tId:transactionId };			YAHOO.log('XHR object created for transaction ' + transactionId, 'info', 'Connection');		}		catch(e)		{			for(var i=0; i<this._msxml_progid.length; ++i){				try				{					// Instantiates XMLHttpRequest for IE and assign to http.					http = new ActiveXObject(this._msxml_progid[i]);					//  Object literal with conn and tId properties					obj = { conn:http, tId:transactionId };					YAHOO.log('ActiveX XHR object created for transaction ' + transactionId, 'info', 'Connection');					break;				}				catch(e){}			}		}		finally		{			return obj;		}	},  /**   * @description This method is called by asyncRequest to create a   * valid connection object for the transaction.  It also passes a   * transaction id and increments the transaction id counter.   * @method getConnectionObject   * @private   * @static   * @return {object}   */	getConnectionObject:function(isFileUpload)	{		var o;		var tId = this._transaction_id;		try		{			if(!isFileUpload){				o = this.createXhrObject(tId);			}			else{				o = {};				o.tId = tId;				o.isUpload = true;			}			if(o){				this._transaction_id++;			}		}		catch(e){}		finally		{			return o;		}	},  /**   * @description Method for initiating an asynchronous request via the XHR object.   * @method asyncRequest   * @public   * @static   * @param {string} method HTTP transaction method   * @param {string} uri Fully qualified path of resource   * @param {callback} callback User-defined callback function or object   * @param {string} postData POST body   * @return {object} Returns the connection object   */	asyncRequest:function(method, uri, callback, postData)	{