var obj_name,top_min,top_max;
function set_top(){
	var d=document;
	if(obj=d.getElementById(obj_name))
		obj.style.top=(d.body.scrollTop>top_min?(d.body.scrollTop>top_max?top_max:d.body.scrollTop):top_min);
}
function activate_menu(name,min,max){
	var d=document;
	if(obj=d.getElementById(name)){
		obj.style.position='absolute';
		obj_name=name;
		top_min=min;
		top_max=max;
		window.onscroll=set_top;
		set_top();
	}
}