jQuery.fn.overlay = function(_options){

	var _options = jQuery.extend({
		opacity: '70',
		color: '#000',
		window_width: '400',
		window_height: '300',
		window_background: '#000',
		close_img: 'images/close.bmp',
		src: '<p>Dit is de overlay</p>'
	}, _options);
	
	return $(this).each(function(){
		var body = $(this);
		var margintop = parseInt(_options.window_height) / 2;
		margintop = margintop + "px";
		var marginleft = parseInt(_options.window_width) / 2;
		marginleft = marginleft + "px";
		
		alert(document.body.scrollHeight);

		body.append('<div id="overlay" style="z-index: 9998; position: absolute; left: 0; top: 0; width: 100%; width: '+document.body.scrollWidth+'; height: 100%; height: '+document.body.scrollHeight+'px; background: '+_options.color+'; opacity:.'+_options.opacity+'; filter: alpha(opacity='+_options.opacity+'); -moz-opacity: 0.'+_options.opacity+';"></div>');
		body.append('<div id="overlay-window" style="margin-top: -'+margintop+'; margin-left: -'+marginleft+'; z-index: 9999;position: absolute; left: 50%; top: 50%; width: '+_options.window_width+'px; height: '+_options.window_height+'px; background: '+_options.window_background+'; overflow: hidden;"><div class="inner_window"><a style="position: absolute; right: 5px; top: 5px; width: 16px; height: 16px;" href="javascript:;" class="close-overlay" id="btn-close-overlay"><img style="border: 0;" src="'+_options.close_img+'" alt="Sluiten" /></a>'+_options.src+'</div></div>');
	
		$("#btn-close-overlay").click(function(event){
			event.preventDefault();
			$("#overlay").remove();
			$("#overlay-window").remove();
		});
	
		window.scroll(0,0);
	});
}