jQuery.extend({
	
    createUploadIframe: function(id, uri) {
        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;
            if (jQuery.browser.opera) { io.src = 'javascript:void(0);'; }
        }
        io.style.position = 'absolute';
        io.style.top = '-1000px';
        io.style.left = '-1000px';
        document.body.appendChild(io);
        return io;			
    },
    createUploadForm: function(id, fileElementId) {
        //create form	
        var formId = 'jUploadForm' + id;
        var fileId = 'jUploadFile' + id;
        var form = $('<form  action="" method="POST" name="' + formId + '" id="' + formId + '" enctype="multipart/form-data"></form>');	
        var oldElement = $('#' + fileElementId);
        var newElement = $(oldElement).clone();
        $(oldElement).attr('id', fileId);
        $(oldElement).before(newElement);
        $(oldElement).appendTo(form);
        //set attributes
        $(form).css('position', 'absolute');
        $(form).css('top', '-1200px');
        $(form).css('left', '-1200px');
        $(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 id = new Date().getTime();        
        var form = jQuery.createUploadForm(id, s.fileElementId);
        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 );
                        // 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 
										{
											$(io).remove();
											$(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);
        }
        // not here
        try {
            // var io = $('#' + frameId);
        		var form = $('#' + formId);
            $(form).attr('action', s.url);
            $(form).attr('method', 'POST');
            $(form).attr('target', frameId);
            if(form.encoding) {
                form.encoding = 'multipart/form-data';				
            } else {				
                form.enctype = 'multipart/form-data';
            }
            $(form).submit();
        } catch(e) {			
            jQuery.handleError(s, xml, null, e);
        }
        // before this
      	if (window.attachEvent) {
            if (jQuery.browser.opera) {
                document.getElementById(frameId).addEventListener('DOMFrameContentLoaded', uploadCallback, false);
            } else {
                document.getElementById(frameId).attachEvent('onload', uploadCallback);
        		}
        } else {
            document.getElementById(frameId).addEventListener('load', uploadCallback, false);
        }
        return {abort: function () {}};
    },
    uploadHttpData: function( r, type ) {
        var data = !type;
        data = type == "xml" || data ? r.responseXML : r.responseText;
        // If the type is "script", eval it in global context
        if ( type == "script" )
            jQuery.globalEval( data );
        // Get the JavaScript object, if JSON is used.
        if ( type == "json" )
            eval( "data = " + data );
        // evaluate scripts within html
        if ( type == "html" )
            jQuery("<div>").html(data).evalScripts();
        //alert($('param', data).each(function(){alert($(this).attr('value'));}));
        return data;
    }
});