Пример можно посмотреть на http://newyearskr.ucoz.ru/
1.Заливаем на сайт все
2.Вставляем после </head>

    		<style type="text/css">
			*{margin: 0;padding: 0;}
			body{
				background: rgb(0,0,17); /* Old browsers */
background: -moz-linear-gradient(top,  rgba(0,0,17,1) 1%, rgba(0,0,51,1) 100%); /* FF3.6+ */
background: -webkit-gradient(linear, left top, left bottom, color-stop(1%,rgba(0,0,17,1)), color-stop(100%,rgba(0,0,51,1))); /* Chrome,Safari4+ */
background: -webkit-linear-gradient(top,  rgba(0,0,17,1) 1%,rgba(0,0,51,1) 100%); /* Chrome10+,Safari5.1+ */
background: -o-linear-gradient(top,  rgba(0,0,17,1) 1%,rgba(0,0,51,1) 100%); /* Opera 11.10+ */
background: -ms-linear-gradient(top,  rgba(0,0,17,1) 1%,rgba(0,0,51,1) 100%); /* IE10+ */
background: linear-gradient(to bottom,  rgba(0,0,17,1) 1%,rgba(0,0,51,1) 100%); /* W3C */
filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#000011', endColorstr='#000033',GradientType=0 ); /* IE6-9 */

			}
		</style>
	</head>
	<body id="body">
		<div id="div" style="width: 100px;height: 100px;"></div>
		<script type="text/javascript" src="js/falling_flakes.js"></script>
		<script type="text/javascript">
			window.onload = function(){
				falling_flakes({
					container: 'body',
					flake: {
						image: 'images/white_flake.png',
						number: 100,
						sizes:{
							width: 20,
							height: 20
						},
						wind_direction: 'random'
					}
				});
			};
		</script>
