jQuery.fn.overlay = function(_options){

	var _options = jQuery.extend({
		opacity: '70',
		color: '#000',
		window_width: '400',
		window_height: '300',
		window_background_color: '#fff',
		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";
		
		var top = body.offset().top;
		
		$('html,body').animate({scrollTop: top}, 500, function(){
		if ($("#overlay").length == 0)
		{
			body.css({
				'overflow' : 'hidden'
			});
			body.append('<div id="overlay" style="z-index: 9998; position: absolute; left: 0; top: 0; width: 100%; height: 100%; 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-color: '+_options.window_background_color+';"><div class="inner_window"><a href="javascript:;" class="close-overlay" id="btn-close-overlay"><img src="'+_options.close_img+'" alt="Sluiten" /></a>'+_options.src+'</div></div>');
		
			$(".close-overlay").click(function(event){
				event.preventDefault();
				$("#overlay").remove();
				$("#overlay-window").remove();
				body.css({
				'overflow' : 'auto'
			});
			});
		
		
		}
		});
	});
}