function list_filter(what,obj){
	lis=$('categories').getElementsByTagName('LI');
	for(var i in lis){
		lis[i].id='';
	}
	obj.parentNode.id='cat-current';
	for(i=65;i<91;i++){
		sect_id='section_'+String.fromCharCode(i);
		if(sect=$(sect_id)){
			if(what>''){
				cnt=0;
				links=sect.getElementsByTagName('A');
				for(j=0;j<links.length;j++){
					if(links[j].rel.indexOf(what)>=0){
						links[j].parentNode.style.display='block';
						cnt++;
					}else{
						links[j].parentNode.style.display='none';
					}
				}
				sect.style.display=(cnt>0?'block':'none');
			}else{
				lis=sect.getElementsByTagName('LI');
				for(j=0;j<lis.length;j++){
					lis[j].style.display='block';
				}
				sect.style.display='block';
			}
		}
	}
}