background-position另类用法
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<title>让我们共同推广WEB标准在中国的发展</title>
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<!--
ul#menu { width:300px; height:300px; margin:0px auto; padding:0px; overflow:hidden; background:transparent url(/articleimg/2006/04/3366/01.jpg)}
ul#menu li { list-style-type:none; float:left; width:100px; height:100px;}
ul#menu li a { display:block; width:100px; height:100px; text-decoration:none; background:transparent url(/articleimg/2006/04/3366/02.jpg) no-repeat 500px 500px;}
a#item1:hover {background-position: 0 0; }
a#item2:hover {background-position: -100px 0;}
a#item3:hover {background-position: -200px 0;}
a#item4:hover {background-position: 0 -100px;}
a#item5:hover {background-position: -100px -100px;}
a#item6:hover {background-position: -200px -100px;}
a#item7:hover {background-position: 0 -200px;}
a#item8:hover {background-position: -100px -200px;}
a#item9:hover {background-position: -200px -200px;}
-->
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<body>
<ul id="menu">
<li><a id="item1" href="#" title="Item 1"> </a></li>
<li><a id="item2" href="#" title="Item 2"> </a></li>
<li><a id="item3" href="#" title="Item 3"> </a></li>
<li><a id="item4" href="#" title="Item 4"> </a></li>
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<li><a id="item6" href="#" title="Item 6"> </a></li>
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<li><a id="item8" href="#" title="Item 8"> </a></li>
<li><a id="item9" href="#" title="Item 9"> </a></li>
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代码:
<style>
ul { width:300px; height:300px; margin:0px auto; padding:0px; overflow:hidden; background:transparent url(image/menu_gray.jpg)}
li {list-style-type:none; width:100px; height:100px; float:left}
li a { display:block; width:100px; height:100px; text-decoration:none;
background:transparent url(image/menu_color.jpg) no-repeat 500px 500px; }
a#item1:hover {background-position: 0 0; }
a#item2:hover {background-position: -100px 0;}
a#item3:hover {background-position: -200px 0;}
a#item4:hover {background-position: 0 -100px;}
a#item5:hover {background-position: -100px -100px;}
a#item6:hover {background-position: -200px -100px;}
a#item7:hover {background-position: 0 -200px;}
a#item8:hover {background-position: -100px -200px;}
a#item9:hover {background-position: -200px -200px;}
</style>
<ul>
<li><a id="item1" href="#" title="Item 1"> </a></li>
<li><a id="item2" href="#" title="Item 2"> </a></li>
<li><a id="item3" href="#" title="Item 3"> </a></li>
<li><a id="item4" href="#" title="Item 4"> </a></li>
<li><a id="item5" href="#" title="Item 5"> </a></li>
<li><a id="item6" href="#" title="Item 6"> </a></li>
<li><a id="item7" href="#" title="Item 7"> </a></li>
<li><a id="item8" href="#" title="Item 8"> </a></li>
<li><a id="item9" href="#" title="Item 9"> </a></li>
</ul>
是不是非常简单，而我们所用到的图片也仅仅是下面的2张而已:
现在我们来分析 background-position 的用法：
A元素一开始的时候背景位置设置成 background-position:500px 500px，而它的大小仅只有100px*100px而已，所以A标签下的所有背景都超过了可视范围无法显示，我们一开始看见的黑白照片就是UL的背景图象。接着当鼠标移动到A元素上的时候，再根据每个A元素所处的位置来分别为他们设置背景的移动大小，这样就形成上面的黑白图片交替效果。#p#分页标题#e#