//dimScreen()
//by Brandon Goldman, corrected a bit by Michal Salaban
jQuery.extend({
	//dims the screen
	dimScreen: function(speed, opacity, callback) {
		if(jQuery('#__dimScreen').size() > 0) return;
		
		if(typeof speed == 'function') {
			callback = speed;
			speed = null;
		}

		if(typeof opacity == 'function') {
			callback = opacity;
			opacity = null;
		}

		if(speed < 1) {
			var placeholder = opacity;
			opacity = speed;
			speed = placeholder;
		}
		
		if(opacity >= 1) {
			var placeholder = speed;
			speed = opacity;
			opacity = placeholder;
		}

		speed = (speed > 0) ? speed : 500;
		opacity = (opacity > 0) ? opacity : 0.5;
		var dim = jQuery('<div></div>').attr({
				id: '__dimScreen'
				,fade_opacity: opacity
				,speed: speed
			}).css({
			background: '#000',
			left: '0',
			opacity: 0,
			position: 'fixed',
			top: '0',
			bottom: '0',
			right: '0',
			zIndex: 999
		}).appendTo($(document.body)).fadeTo(speed, opacity, callback);
		$('body').css('height', dim.height()).css('overflow', 'hidden')
	},
	
	//stops current dimming of the screen
	dimScreenStop: function(callback) {
		var x = jQuery('#__dimScreen');
		var opacity = x.attr('fade_opacity');
		var speed = x.attr('speed');
		x.fadeOut(speed, function() {
			x.remove();
			if(typeof callback == 'function') callback();
		});
		$('body').css('height', null).css('overflow', 'visible')
	}
});