下雪了javascript實現雪花飛舞_javascript技巧

*{
 margin:0;
 padding:0;
 list-style: none;
 border: none;
}
body{
 width: 100%;
 height:600px;
 background:#000;
}
.snow_parent{
 position: relative;
 width: 100%;
 height:100%;
 overflow: hidden;
 margin: 0 auto;
}
.snow_parent div.parent{
 background-image: url(../img/snow.png);
 float: left;
 -webkit-transform: scale(.1);
 -moz-transform: scale(.1);
 -o-transform: scale(.1);
 -ms-transform: scale(.1);
 transform: scale(.1);
 position: absolute;
}
.snow_one{
 width: 180px;
 height: 180px;
 background-position:0 0;
 background-repeat: no-repeat;
 left:-70px;
 top: -95px;
}
.snow_two{
 width: 140px;
 height: 140px;
 background-position:-220px -18px;
 left:-30px;
 top: -75px;
}
.snow_three{
 width:150px;
 height: 150px;
 background-position:-400px -15px;
 left:-20px;
 top: -80px;
}
.snow_four{
 width: 160px;
 height: 160px;
 background-position:-10px -206px; 
}
.snow_four{
 left:-10px;
 top: -85px;
}