jq + css 实现简单的图片轮播效果

jq + css 实现简单的图片轮播效果

开发过程中需要用到图片轮播的插件，在网上找了几个插件之后还是决定自己码一个，比较简洁的功能，以后说不定还会有用。

ps：
功能比较简单，整个框并不能根据图片的大小自动调节，这里所用的图片是1170*500的，如果需要改成其他大小的图片，自行修改.pic-list下img的宽度。

.pic-list中的宽度为整个横幅的宽度，如果需要轮播的图片数量很多，.pic-list的宽度应大于数量*单张宽度，

html

<div class="banner">
        
    <div class="pic-list" style="left: -1170px">
        <img src="/static/img/4.jpg" alt="">
        <img src="/static/img/1.jpg" alt="">
        <img src="/static/img/2.jpg" alt="">
        <img src="/static/img/3.jpg" alt="">
        <img src="/static/img/4.jpg" alt="">
        <img src="/static/img/1.jpg" alt="">
    div>
    <div id="buttons">
        
        <span class='on'>span>
        <span>span>
        <span>span>
        <span>span>
    div>
    <a href="javascript:;" class="arrow" id="prev"><a>
    <a href="javascript:;" class="arrow" id="next">>a>
div>

css

.banner{
    width: 100%;
    height: 500px;
    overflow: hidden;
    position: relative;

}
.banner a{
    text-decoration: none;
}
.banner .pic-list{
    width: 10000px;
    height: 500px;
    position: absolute;
    z-index: 1;
}
.banner .pic-list img{
    width: 1170px;
    float: left;
}
#buttons{
    position: absolute;
    z-index: 2;
    height: 10px;
    bottom: 20px;
    left: 550px;

}
#buttons span{
    cursor: pointer;
    float: left;
    border: 1px solid #fff;
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background: #333;
    margin-right: 5px;
}
#buttons .on{
    background: orange;
}
.arrow{
    cursor: pointer;
    line-height: 36px;
    text-align: center;
    font-size: 20px;
    font-weight: bold;
    width: 40px;
    height: 40px;
    position: absolute;
    z-index: 2;
    top: 200px;
    background: rgba(0,0,0,0.5);
    color: #fff;
    display: none;
}
.banner:hover .arrow{display: block;}

#prev{
    left: 20px;
}
#next{
    right:20px;
}

js

$(document).ready(function(){
    var picNum = 4;//图片数量，根据实际修改
    var picWidth = 1170;//图片的宽度，根据实际修改
    var picMaxWidth = -1 * picNum * picWidth;
    var currentPic = 1;
    var next = $('#next');
    var prev = $('#prev');
    var flag = false;

    prev.on('click',function(){
        if(!flag){
            calPx(1170);
            currentPic--;
            if (currentPic < 1) {
                currentPic = picNum;
            }
            $('#buttons span').eq(currentPic-1).addClass('on').siblings().removeClass('on');
        }
    });

    next.on('click',function(){
        if(!flag){
            calPx(-1170);
            currentPic++;
            if (currentPic > picNum) {
                currentPic = 1;
            }
            $('#buttons span').eq(currentPic-1).addClass('on').siblings().removeClass('on');
        }


    });
    $('.banner').on('mouseover',function(){
        stop();
    }).on('mouseout',function(){
        play();
    })
    function nextClick(){
        next.click();
    }
    function play(){
        setInt = setInterval(nextClick,2000);
    }
    function stop(){
        clearInterval(setInt);
    }

    function calPx(leftPx){
        flag = true;
        var left = parseInt($('.pic-list').css('left'));
        var newLeft = left+leftPx;
        var time = 300;
        var interval = 10;
        var speed = leftPx/(time/interval);

        function go(){
            var left = parseInt($('.pic-list').css('left'));
            if((speed < 0 && left > newLeft) || (speed > 0 && left < newLeft)){
                $('.pic-list').css('left', (left + speed) + 'px');
                setTimeout(go,interval);
            }else{
                flag = false;
                if( newLeft > -1170){
                    newLeft = picMaxWidth;
                }else if (newLeft < picMaxWidth ) {
                    newLeft = -1170;
                }
                $('.pic-list').css('left',newLeft + 'px');
            }
        }
        go();

    }
    play();

});