下面我们利用CSS3的animation写出这样的动画来,要点就是: 用动画不停改变背景图片位置; 动画高为无限循环; 在页面放三个DIV,首先将他们大小铺满整个窗口,这点是通过将其position设为absolute然后分别设置上左下右四个方面距离为0px达到的。 <!doctype html> <html> <head> <title>Moving stars</title> <style type="text/css">
html,body{
margin: 0;
} .wall{ position: absolute; top: 0; left: 0; bottom: 0; right: 0; } div#background{
background: black url('img/background.png') repeat-x 5% 0%; } div#midground{ background:url('img/midground.png')repeat 20% 0%; z-index: 1; } div#foreground{ background:url('img/foreground.png')repeat 35% 0%; z-index: 2; } </style> </head> <body> <div id="background" class="wall"></div> <div id="midground" class="wall"></div> <div id="foreground" class="wall"></div> </body> </html> 然后定义的们的动画,让背景图片的位置从开始的0%变化到600%,注意我们只改变x方向的位置,y保持0%不变,因为我们想要的效果是水平移动,所以y方向无变化。 @-webkit-keyframes STAR-MOVE { from { background-position:0% 0% } to { background-position: 600% 0% } } @keyframes STAR-MOVE { from { background-position: 0% 0% } to { background-position: 600% 0% } } 最后一步便是将动画关键帧应用到三个充当背景的DIV上。 div#background { background: black url('img/background.png') repeat-x 5% 0%; -webkit-animation: STAR-MOVE 200s linear infinite; -moz-animation: STAR-MOVE 200s linear infinite; -ms-animation: STAR-MOVE 200s linear infinite; animation: STAR-MOVE 200s linear infinite; } div#midground { background: url('img/midground.png')repeat 20% 0%; z-index: 1; -webkit-animation: STAR-MOVE 100s linear infinite; -moz-animation: STAR-MOVE 100s linear infinite; -ms-animation: STAR-MOVE 100s linear infinite; animation: STAR-MOVE 100s linear infinite; } div#foreground { background: url('img/foreground.png')repeat 35% 0%; z-index: 2; -webkit-animation: STAR-MOVE 50s linear infinite; -moz-animation: STAR-MOVE 50s linear infinite; -ms-animation: STAR-MOVE 50s linear infinite; animation: STAR-MOVE 50s linear infinite; } 飘动的浮云 如果把上面的星星图片换成云彩,那就成了飘动的浮云了。 代码需要小的改动,就是背景层需要设置background-size为cover,这样才能让蓝天铺满窗口。 div#background { background: black url('img/background.png') repeat-x 5% 0%; background-size: cover; -webkit-animation: STAR-MOVE 200s linear infinite; -moz-animation: STAR-MOVE 200s linear infinite; -ms-animation: STAR-MOVE 200s linear infinite; animation: STAR-MOVE 200s linear infinite; }