// Creo il tag DIV su cui tracciare il rettangolo
function createLayer(name, left, top, width, height, visible, bg) {
	var layer;
	if (document.layers) {
		document.writeln('<layer name="' + name + '" left=' + left + ' top=' + top + ' width=' + width + ' height=' + height +  ' visibility=' + (visible ? '"show"' : '"hide"') + ' bgcolor=' + bg + '></layer>');
		layer = getLayer(name);
		layer.width = width;
		layer.height = height;
	}
	else {
		document.writeln('<div id="' + name + '" style="background-color: '+ bg +'; position:absolute; overflow:none; left:' + left + 'px; top:' + top + 'px; width:' + width + 'px; height:' + height + 'px;' + ' visibility:' + (visible ? 'visible;' : 'hidden;') +  '"></div>');
	}
	clipLayer(name, 0, 0, width, height);
}

// Recupero il tag DIV su cui tracciare una delle linee del rettangolo
function getLayer(name) {
	if (document.layers)
		return(document.layers[name]);
	else if (document.all || (navigator.appName == "Netscape" && parseInt(navigator.appVersion) == 5)) {
		if (eval(document.getElementById(name)) != null) {
			layer = eval(document.getElementById(name).style);
			return(layer);
		} else
			return(null);
	}
	else
		return(null);
}

// move layer to x,y
function moveLayer(name, x, y) {
	var layer = getLayer(name);
	if (layer != null) {
		if (document.layers) {
			layer.moveTo(x, y);
		}
		else {
			layer.left = x;
			layer.top  = y;
		}
	}
}

// toggle layer to invisible
function hideLayer(name) {
	var layer = getLayer(name);
	if (layer != null) {
		if (document.layers)
			layer.visibility = "hide";
		if (document.all)
			layer.visibility = "hidden";
	}
}

// toggle layer to visible
function showLayer(name) {
	var layer = getLayer(name);
	if (layer != null) {
		if (document.layers)
			layer.visibility = "show";
		else
			layer.visibility = "visible";
	}
}

// clip layer display to clipleft, cliptip, clipright, clipbottom
// Visualizza le linee del rettangolo
function clipLayer(name, clipleft, cliptop, clipright, clipbottom) {
	//window.status = 'L=' + clipleft + 'T=' + cliptop + 'R=' + clipright + 'B=' + clipbottom;
	var layer = getLayer(name);
	if (layer != null) {
		if (document.layers){
			layer.clip.left = clipleft;
			layer.clip.top = cliptop;
			layer.clip.right = clipright;
			layer.clip.bottom = clipbottom;
		}
		else {
			layer.clip = 'rect(' + cliptop + ' ' +  clipright + ' ' + clipbottom + ' ' + clipleft +')';
		}
	}
}