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.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);
				}
				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;
    }
})