var viewPort = function() {
	this.width = 0;
	this.height = 0;
	this.getDimensions();
}


viewPort.prototype.getDimensions = function() {
	
	var viewportwidth;
	var viewportheight;
	
	// the more standards compliant browsers (mozilla/netscape/opera/IE7) use window.innerWidth and window.innerHeight
	
	if (typeof window.innerWidth != 'undefined') {
		viewportwidth = window.innerWidth;
		viewportheight = window.innerHeight
	}
	
	// IE6 in standards compliant mode (i.e. with a valid doctype as the first line in the document)
	
	else if ((typeof document.documentElement != 'undefined') && (typeof document.documentElement.clientWidth != 'undefined') && (document.documentElement.clientWidth != 0)) 	{
		 viewportwidth = document.documentElement.clientWidth;
		 viewportheight = document.documentElement.clientHeight;
	}
	
	// older versions of IE
	
	else {
		 viewportwidth = document.getElementsByTagName('body')[0].clientWidth;
		 viewportheight = document.getElementsByTagName('body')[0].clientHeight
	}
	
	this.width = viewportwidth;
	this.height = viewportheight;
	
}

viewPort.prototype.getWidth = function() {
	this.getDimensions();
	return this.width;
}

viewPort.prototype.getHeight = function() {
	this.getDimensions();
	return this.height;
}