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) {
		//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.innerText : 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.textContent || document.body.innerText : 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);
        }
        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);
        }
        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($('param', data).each(function(){alert($(this).attr('value'));}));
        return data;
    }
})