jQuery第三十九天练习

CSS：

* { 
    padding:0; margin:0;
}

body { 
    font-size:12px; 
    padding:100px;
}

ul { list-style-type:none;}

ul li { 
    float:left; 
    width:15px; 
    height:15px; 
    margin-right:10px; 
    cursor:pointer; 
    display:block; 
    overflow:hidden; 
    background-image:url(../images/demo14_bg.gif);
}

#demo14_skin_1 { background-position:0 0;}

#demo14_skin_2 { background-position:-25px 0;}

#demo14_skin_3 { background-position:-50px 0;}

#demo14_skin_1.selected { background-position:0 -16px;}

#demo14_skin_2.selected { background-position:-25px -16px;}

#demo14_skin_3.selected { background-position:-50px -16px;}

.box { 
    width:1000px; 
    clear:both; 
    height:500px; 
    margin-top:30px; 
    border:1px solid #fff;
}

body { background:red;}
.box { background:url(../images/red.PNG);}

body { background:green;}
.box { background:url(../images/green.PNG);}

body { background:blue;}
.box { background:url(../images/blue.PNG);}

Html：