//-------- LAYER SUPPORT FUNCTIONS --------------
// 

// clip layer display to clipleft, cliptip, clipright, clipbottom
function clipLayer(name, clipleft, cliptop, clipright, clipbottom) {		
	var layer = getLayer(name);		
	if (layer != null) {
  	    if (isNav4) { 
			layer.clip.left   = clipleft;
			layer.clip.top    = cliptop;
			layer.clip.right  = clipright;
			layer.clip.bottom = clipbottom;
	    } else {
			layer.clip = 'rect(' + cliptop + ' ' +  clipright + ' ' + clipbottom + ' ' + clipleft +')';
	    }
	}
}

// Create a DHTML layer
function createLayer(name, left, top, width, height, visible, content) {
	  var layer;
	  if (isNav4) {
	    document.writeln('<layer name="' + name + '" left=' + left + ' top=' + top + ' width=' + width + ' height=' + height +  ' visibility=' + (visible ? '"show"' : '"hide"') +  '>');
	    document.writeln(content);
	    document.writeln('</layer>');
	    layer = getLayer(name);
	    layer.width = width;
	    layer.height = height;
	  } else {
	    document.writeln('<div id="' + name + '" style="position:absolute; overflow:none; left:' + left + 'px; top:' + top + 'px; width:' + width + 'px; height:' + height + 'px;' + ' visibility:' + (visible ? 'visible;' : 'hidden;') +  '">');
	    document.writeln(content);
	    document.writeln('</div>');
	  }
	  clipLayer(name, 0, 0, width, height);
}

// get the layer object called "name"
function getLayer(name) {
	  if (isNav4)
	    return(document.layers[name]);
	  else if (isIE4) {
	  	if ( eval('document.all.' + name) != null) {
		    layer = eval('document.all.' + name + '.style');
		    return(layer);
		} else
			return(null);
	  } else if (is5up) {
		var theObj = document.getElementById(name);
		return theObj.style
	  } else
	    return(null);
}

// toggle layer to invisible
function hideLayer(name) {		
  	var layer = getLayer(name);		
	if (layer != null) {
	 	if (isNav4)
    			layer.visibility = "hide";
		else
   			layer.visibility = "hidden";
	}
}

// move layer to x,y
function moveLayer(name, x, y) {		
  	var layer = getLayer(name);		
	if (layer != null) {
	  	if (isNav4)
    		layer.moveTo(x, y);
	 	else if (isIE) {
    			layer.left = x + "px";
   			layer.top  = y + "px";
		} else {
			layer.height = iHeight - y;
			layer.width  = iWidth - x;
    			layer.left = x + "px";
   			layer.top  = y + "px";
	  	}
	}
}

// replace layer's content with new content
function replaceLayerContent(name, content) {
	  if (isNav4) {
		    var layer = getLayer(name);
			if (layer != null) {
			    layer.document.open();
			    layer.document.writeln(content);
			    layer.document.close();
			}
	  }  else if (isIE) {
			if (eval("document.all." + name) != null) {
		  		content = content.replace(/\'/g,"\\'");
			    var str = "document.all." + name + ".innerHTML = '" + content + "'";
			    eval(str);
			}
	  }
}

// set layer background color
function setLayerBackgroundColor(name, color) {		
  	var layer = getLayer(name);		
	if (layer != null) {
	    if (isNav4) 
    		layer.bgColor = color;
	    else 
    		layer.backgroundColor = color;
	}
}

// toggle layer to visible
function showLayer(name) {		
  	var layer = getLayer(name);		
	if (layer != null) {
	  	if (isNav4)
    			layer.visibility = "visible";
		else
   		 	layer.visibility = "visible";
	}
}