function blocking(nr) {
	
	alllayers = new Array("layer1","layer2","layer3","layer4","layer5","layer6","layer7","layer8","layer9");
	
	if (document.layers)
	{
		var i = 0;
		
		for (i = 0; i <= (alllayers.length - 1); i++) {
		  looplayer = alllayers[i];
		  if (alllayers[i] == nr) {
			if (document.layers[nr].display == 'none') {
				current = (document.layers[nr].display == 'none') ? 'block' : 'block';
				document.layers[nr].display = current;
		  	} else {
				current = (document.layers[nr].display == 'none') ? 'none' : 'none';
				document.layers[nr].display = current;
			}
		  } else {
		    current = (document.layers[looplayer].display == 'none') ? 'none' : 'none';
			document.layers[looplayer].display = current;
		  }
		}
	}
	else if (document.all)
	{
		var i = 0;
		
		for (i = 0; i <= (alllayers.length - 1); i++) {
		  looplayer = alllayers[i];
		  if (alllayers[i] == nr) {
			if (document.all[nr].style.display == 'none') {
				current = (document.all[nr].style.display == 'none') ? 'block' : 'block';
				document.all[nr].style.display = current;
		  	} else {
				current = (document.all[nr].style.display == 'none') ? 'none' : 'none';
				document.all[nr].style.display = current;
			}
		  } else {
		    current = (document.all[looplayer].style.display == 'none') ? 'none' : 'none';
			document.all[looplayer].style.display = current;
		  }
		}
	}
	else if (document.getElementById)
	{
		var i = 0;
		
		for (i = 0; i <= (alllayers.length - 1); i++) {
		  looplayer = alllayers[i];
		  if (alllayers[i] == nr) {
			if (document.getElementById(nr).style.display == 'none') {
				vista = (document.getElementById(nr).style.display == 'none') ? 'block' : 'block';
				document.getElementById(nr).style.display = vista;
		  	} else {
				vista = (document.getElementById(nr).style.display == 'none') ? 'none' : 'none';
				document.getElementById(nr).style.display = vista;
			}
		  } else {
		    vista = (document.getElementById(looplayer).style.display == 'none') ? 'none' : 'none';
			document.getElementById(looplayer).style.display = vista;
		  }
		  
		}
	}

}