function _showhide(part) {
    	if (getElementById(part)!='')
    	if (document.getElementById(part).style.display=='none')
    		document.getElementById(part).style.display='';
   	else document.getElementById(part).style.display='none';
   }

	var last_changed = null;
	function showhide(elem)	{
		if(elem != null && 	!(typeof(elem) == 'object'))
			if(!(elem = document.getElementById(elem))) return;
		if (elem.style.display == 'none')
				elem.style.display = '';
		else
			elem.style.display = 'none';
	}

	function update_width(){
		// using prototype
		left = $('bar_left').getWidth();
		middle = $('box_center').getWidth();
		right = $('bar_right').getWidth();
		document.getElementById('wrapper').setStyle('width:'+parseInt(left+middle+right+12)+'px;');
	}