The source code

    Ext.ux.SlidingPager = Ext.extend(Object, {
        init : function(pbar){
            Ext.each(pbar.items.getRange(2,6), function(c){
                c.hide();
            });
            var slider = new Ext.Slider({
                width: 114,
                minValue: 1,
                maxValue: 1,
                plugins: new Ext.ux.SliderTip({
                    getText : function(s){
                        return String.format('Page {0} of {1}', s.value, s.maxValue);
                    }
                }),
                listeners: {
                    changecomplete: function(s, v){
                        pbar.changePage(v);
                    }
                }
            });
            pbar.insert(5, slider);
            pbar.on({
                change: function(pb, data){
                    slider.maxValue = data.pages;
                    slider.setValue(data.activePage);
                },
                beforedestroy: function(){
                    slider.destroy();
                }
            });
        }
    });