function JSW_DisplayManager()
{
	this.hideObject = function(theObject)
	{
		// hides specified object
	}
	this.showObject = function(theObject)
	{
		// shows specified object
	}
	this.setAlpha = function(obj, value)
	{
	    // set transparence of object
	}
}
function JSW_DisplayManagerMicrosoft()
{
	JSW_DisplayManagerMicrosoft.prototype = new JSW_DisplayManager();
	this.showObject = function(theObject)
	{
		theObject.style.visibility = "visible";
	}
	this.hideObject = function(theObject)
	{
		theObject.style.visibility = "hidden";
	}
	this.setAlpha = function(obj, value)
	{
	    var alphaval = value * 100;
	    obj.style.filter = "Alpha(opacity="+alphaval+")";
	}
}
function JSW_DisplayManagerOpera()
{
	JSW_DisplayManagerOpera.prototype = new JSW_DisplayManager();
	this.showObject = function(theObject)
	{
		theObject.style.visibility = "visible";
	}
	this.hideObject = function(theObject)
	{
		theObject.style.visibility = "hidden";
	}
}
function JSW_DisplayManagerNetscape()
{
	JSW_DisplayManagerNetscape.prototype = new JSW_DisplayManager();
	this.showObject = function(theObject)
	{
		theObject.style.visibility = "visible";
	}
	this.hideObject = function(theObject)
	{
		theObject.style.visibility = "hidden";
	}
	this.setAlpha = function(obj, value)
	{
	    obj.style.MozOpacity = value;
	}	
}