Как задать начальное значение для такого ползунка?

var values = [1, 20, 50, 100],
                marks = $('#marks p');
            for (var i = 0; i < values.length; i++) {
                marks.eq(i).css('left', values[i] + '%');
            }
            var slider = $("#slider").slider(
                    {
                        value: 50,/*вот эта строчка*/
                        slide: function (event, ui) {
                            var incLeft = event.which != $.ui.keyCode.RIGHT,
                                    incRight = event.which != $.ui.keyCode.LEFT;
                            slider.slider('option', 'value', findNearest(incLeft, incRight, ui.value));
                            return false;
                        },
                        stop: function (event, ui) {
                            marks.removeClass('active');
                            marks.eq(values.indexOf(ui.value)).addClass('active');
                        }
                    });
            function findNearest(incLeft, incRight, value) {
                var nearest = null,
                        diff = null;
                for (var i = 0; i < values.length; i++) {
                    if ((incLeft && values[i] <= value) || (incRight && values[i] >= value)) {
                        var newDiff = Math.abs(value - values[i]);
                        if (diff == null || newDiff < diff) {
                            nearest = values[i];
                            diff = newDiff;
                        }
                    }
                }
                return nearest;
            }