function showTooltip(x, y, contents) {

    $('<div id="tooltip">' + contents + '</div>').css({

        position: 'absolute',

        display: 'none',

        top: y + 5,

        left: x + 5,

        border: '1px solid #fdd',

        padding: '2px',

        'background-color': '#fee',

        opacity: 0.80

    }).appendTo("body").fadeIn(200);

}

var previousPoint = null;

function onPlotHover(event, pos, item) {

    var $fig = $(event.target);

    if (item) {

        if (previousPoint != item.datapoint) {

            previousPoint = item.datapoint;

            $("#tooltip").remove();

            var x = item.datapoint[0].toFixed(2),

                y = item.datapoint[1].toFixed(2);

            if ($fig.data('mode') == 'time') {

                x = new Date(item.datapoint[0]);

                var dateformat = $fig.data('dateformat');

                if (dateformat) {

                    x = x.strftime(dateformat);

                } else {

                    x = x.toLocaleDateString() + ' ' + x.toLocaleTimeString();

                }

            } else if (item.datapoint.length == 4) {

                // NOTE: this has no chance to work with jquery flot >= 0.6 because

                // jquery flot normalizes datapoints and only keeps 2 columns. Either

                // use processRawData hook or use the 'dateformat' option.

                x = new Date(item.datapoint[2]);

                x = x.strftime(item.datapoint[3]);

            }

            showTooltip(item.pageX, item.pageY, item.series.label + ': (' + x + ' ; ' + y + ')');

        }

    } else {

        $("#tooltip").remove();

        previousPoint = null;

    }

}