cm_banner_list li{

display: none;
position: absolute;
top: 0;
left: 0;
}

.cm-banner-num {
width: 100%;
position: absolute;
bottom: 0;
text-align: center;
z-index: 2; /如果没有在这里设置层次小圆点的点击效果无法触发/
}

.cm-banner-num li{
width: 10px;
margin: 10px 3px;
height: 10px;
background-color: #fff;
border-radius: 5px;
-webkit-border-radius: 5px;
display: inline-block;
opacity: 0.7;
}

.cm-banner-num .active {
background-color: #3982de;
}

.cm-banner-arrow {
position: absolute;
top: 50%;
margin-top: -22px;
opacity: 0.5;
display: none;
}

cm_prev {

left: 0;
}

cm_next {

right: 0;
}

//鼠标移入箭头按钮高亮
$('.cm-banner-arrow').hover(function(){
$(this).css('opacity','1');
},function(){
$(this).css('opacity','0.5');
});

//初始化必要变量
var i = 0;
var cm_length = $('#cm_banner_list li').length;
var cm_toggle = function(point){
$('#cm_banner_num li').eq(point).addClass('active').siblings().removeClass('active');
};

//动态添加小圆点
for(j = 0;j < cm_length;j++){
$('#cm_banner_num').append('

//给第一个小圆点添加样式
$('#cm_banner_num li').first().addClass('active');

//给第一张图片添加样式
$('#cm_banner_list li').first().css('display','block');

//鼠标点击左箭头切换
$('#cm_prev').click(function(){
i--;
if(i < 0){
i = cm_length - 1;
}
$('#cm_banner_list li').eq(i).fadeIn(800).siblings().fadeOut(800);
cm_toggle(i);
});

//鼠标点击右箭头切换
$('#cm_next').click(function(){
i++;
if(i > cm_length - 1){
i = 0;
}
$('#cm_banner_list li').eq(i).fadeIn(800).siblings().fadeOut(800);
cm_toggle(i);
});

//鼠标点击圆点切换
$('#cm_banner_num li').click(function(){
var cm_index = $(this).index();
$('#cm_banner_list li').eq(cm_index).fadeIn(800).siblings().fadeOut(800);
i = cm_index;
cm_toggle(cm_index);
});

//自动播放
cm_timer = setInterval(function(){
i++;
if(i > cm_length - 1){
i = 0;
}
$('#cm_banner_list li').eq(i).fadeIn(800).siblings().fadeOut(800);
cm_toggle(i);
},2500);
});