function makeScrollbar(content,scrollbar,handle,horizontal,ignoreMouse){
var steps = (horizontal?(content.getScrollSize().x - content.getSize().x):(content.getScrollSize().y - content.getSize().y));
var slider = new Slider(scrollbar, handle, {
steps: steps,
mode: (horizontal?'horizontal':'vertical'),
onChange: function(step){

var x = (horizontal?step:0);
var y = (horizontal?0:step);
content.scrollTo(x,y);
}
}).set(0);
if( !(ignoreMouse) ){

$$(content, scrollbar).addEvent('mousewheel', function(e){
e = new Event(e).stop();
var step = slider.step - e.wheel * 30;
slider.set(step);
});
}
$(document.body).addEvent('mouseleave',function(){slider.drag.stop()});
};

window.addEvent('domready', function(){

/* crea la scrollbar se c'\350 del contenuto invisibile */
if(document.getElementById("scroll_content").scrollHeight>560){

makeScrollbar( $('scroll_content'), $('scroll_bar'), $('scroll_handle') );
}
else{

document.getElementById("scroll_bar").style.display="none";
}
});