function SlideNavs(val){
	if(document.active_nav!==true){
		show(val);
	}else{
		if(val!=document.active_nav_id){
		var restore=document.getElementById(document.active_nav_id);
		document.getElementById('nav_'+document.active_nav_id).className = '';
		document.getElementById('nav_'+val).className = 'nav_chosen';
		new Effect.SlideUp(restore, {duration:0.5, afterFinish:function(){show(val);}});
		}else{
			var restore=document.getElementById(document.active_nav_id);
			new Effect.SlideUp(restore, {duration:0.5});
			document.active_nav=false;
			document.getElementById('nav_'+document.active_nav_id).className = '';
		}
	}
}
	
function show(val){
	new Effect.SlideDown(val, {duration:0.5});
		document.getElementById('nav_'+val).className = 'nav_chosen';
		document.active_nav=true;
		document.active_nav_id=val;
}