jQuery.extend({

	createUploadIframe: function(id, uri) {
		//create frame
		var frameId = 'jUploadFrame' + id;

		if(window.ActiveXObject) {
			var io = document.createElement('<iframe id="' + frameId + '" name="' + frameId + '" />');
			if(typeof uri== 'boolean'){
				io.src = 'javascript:false';
			}
			else if(typeof uri== 'string'){
				io.src = uri;
			}
		}
		else {
			var io = document.createElement('iframe');
			io.id = frameId;
			io.name = frameId;
		}

		io.style.position = 'absolute';
		io.style.top = '-1000px';
		io.style.left = '-1000px';

		document.body.appendChild(io);

		return io
	},

	createUploadForm: function(id, fileElementId, file_name) {

		//create form
		var formId = 'jUploadForm' + id;
		var fileId = 'jUploadFile' + id;
		var form = jQuery('<form  action="" method="POST" name="' + formId + '" id="' + formId + '" enctype="multipart/form-data"><input type="hidden" name="file_name" value="' + file_name + '"></form>');
		var oldElement = jQuery(fileElementId);
		var newElement = jQuery(oldElement).clone();

		jQuery(oldElement).attr('id', fileId);
		jQuery(oldElement).before(newElement);
		jQuery(oldElement).appendTo(form);

		//set attributes
		jQuery(form).css('position', 'absolute');
		jQuery(form).css('top', '-1200px');
		jQuery(form).css('left', '-1200px');
		jQuery(form).appendTo('body');
		return form;
	},

	ajaxFileUpload: function(s) {
			// TODO introduce global settings, allowing the client to modify them for all requests, not only timeout
			s = jQuery.extend({}, jQuery.ajaxSettings, s);

			var file_name = s.data;

			var id = new Date().getTime();
			var fileElement = (s.fileElement)? s.fileElement : "#" + s.fileElementId;
			var form = jQuery.createUploadForm(id, fileElement, file_name);
			var io = jQuery.createUploadIframe(id, s.secureuri);
			var frameId = 'jUploadFrame' + id;
			var formId = 'jUploadForm' + id;

			// Watch for a new set of requests
			if ( s.global && ! jQuery.active++ ) {
				jQuery.event.trigger( "ajaxStart" );
			}

			var requestDone = false;
			// Create the request object
			var xml = {}
			if ( s.global ) {
				jQuery.event.trigger("ajaxSend", [xml, s]);
			}

			// Wait for a response to come back
			var uploadCallback = function(isTimeout) {
				var io = document.getElementById(frameId);
				try {

					if(io.contentWindow) {

						xml.responseText = io.contentWindow.document.body?io.contentWindow.document.body.innerHTML:null;
						xml.responseXML = io.contentWindow.document.XMLDocument?io.contentWindow.document.XMLDocument:io.contentWindow.document;
					} else if(io.contentDocument) {

						xml.responseText = io.contentDocument.document.body?io.contentDocument.document.body.innerHTML:null;
						xml.responseXML = io.contentDocument.document.XMLDocument?io.contentDocument.document.XMLDocument:io.contentDocument.document;
					}
				}catch(e) {
					jQuery.handleError(s, xml, null, e);
				}

				if ( xml || isTimeout == "timeout") {

					requestDone = true;
					var status;

					try {
						status = isTimeout != "timeout" ? "success" : "error";
						// Make sure that the request was successful or notmodified
						if ( status != "error" ) {

							// process the data (runs the xml through httpData regardless of callback)
							var data = jQuery.uploadHttpData( xml, s.dataType );

							// If a local callback was specified, fire it and pass it the data
							if ( s.success )
								s.success( data, status, xml.responseText );

							// Fire the global callback
							if( s.global )
									jQuery.event.trigger( "ajaxSuccess", [xml, s] );
						} else {

							jQuery.handleError(s, xml, status);
						}
					} catch(e) {

						status = "error";
						jQuery.handleError(s, xml, status, e);
					}

					// The request was completed
					if( s.global ) {
						jQuery.event.trigger( "ajaxComplete", [xml, s] );
					}

					// Handle the global AJAX counter
					if ( s.global && ! --jQuery.active ) {
						jQuery.event.trigger( "ajaxStop" );
					}

					// Process result
					if ( s.complete ) {
						s.complete(xml, status);
					}

					jQuery(io).unbind()

					setTimeout(function() {

						try {
								jQuery(io).remove();
								jQuery(form).remove();

						} catch(e) {

							jQuery.handleError(s, xml, null, e);
						}

					}, 100)

					xml = null

				}
			}

			// Timeout checker
			if ( s.timeout > 0 ) {
					setTimeout(function(){
							// Check to see if the request is still happening
							if( !requestDone ) uploadCallback( "timeout" );
					}, s.timeout);
			} try {
		   // var io = jQuery('#' + frameId);
				var form = jQuery('#' + formId);
				jQuery(form).attr('action', s.url);
				jQuery(form).attr('method', 'POST');
				jQuery(form).attr('target', frameId);
				if(form.encoding) {
					form.encoding = 'multipart/form-data';
				} else {
					form.enctype = 'multipart/form-data';
				}

				jQuery(form).submit();

		} catch(e) {

					jQuery.handleError(s, xml, null, e);
		}
		if(window.attachEvent){
			document.getElementById(frameId).attachEvent('onload', uploadCallback);
		}
		else{
			document.getElementById(frameId).addEventListener('load', uploadCallback, false);
		}
		return {abort: function () {}};

	},

	uploadHttpData: function( r, type ) {
		var data = !type;
		data = type == "xml" || data ? r.responseXML : r.responseText;
		// If the type is "script", eval it in global context
		if ( type == "script" )
			jQuery.globalEval( data );
		// Get the JavaScript object, if JSON is used.
		if ( type == "json" )
			eval( "data = " + data );
		// evaluate scripts within html
		if ( type == "html" )
			jQuery("<div>").html(data).evalScripts();
			//alert(jQuery('param', data).each(function(){alert(jQuery(this).attr('value'));}));
		return data;
	}
})