var IE = document.all?true:false;
function showDescr(id)
{
	var main1 = document.getElementById('descr1');
	for(var i=1; main1 != null;i++)
	{
		main1.style.visibility = 'hidden';
		main1.style.position = 'absolute';
		main1 = document.getElementById('descr'+(i+1));
	}
	var main2 = document.getElementById('descr'+id);
	main2.style.position = (IE) ? 'fixed' : 'inherit';
	main2.style.visibility = 'visible';
}