Example of JavaScript imitating Taobao to achieve magnifying glass effect-JS Tutorial-php.cn

Example of JavaScript imitating Taobao to achieve magnifying glass effect

黄舟

Release： 2017-11-24 09:41:15

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We all knowMagnifying glass effect is generally used in some shopping malls. For example, whenever we open Taobao, Tmall and other PC terminals, when we see the items we like and click on the picture, It gives the effect of a magnifying glass. When you don’t understand and analyze its principle, it feels very magical. When you really get in touch with it, it is also very easy to understand. In the previous article, we also introduced an example of JavaScript implementing a magnifying glass. Today we will introduce to you the JavaScript imitation An example of how Taobao achieves the magnifying glass effect!

We divide the entire layout into three parts. The first part is the small picture of the theme, which is placed in the upper left corner of the entire layout; the second part is the picture list below, directly below the small picture; The last part is the magnifying glass display part, position it to the right of the small picture.
Then use js to add basic events (including mouse movement in and out, etc.) For detailed internal usage, see the following code

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title></title>
    <style>
        ul{
            list-style: none;
            padding: 0;
        }
        .zoom-box{
            width: 452px;
            position: relative;
        }
        .small-box{
            position: relative;
            border: 1px solid #ccc;
        }
        .small-box img{
            width: 100%;
            height: 100%;
        }
        .small-box .square{
            position: absolute;
            left: 0;
            top: 0;
            background: yellow;
            opacity: 0.5;
            /*display: none;*/
        }
        .small-box .mask{
            width: 100%;
            height: 100%;
            position: absolute;
            top: 0;
            left: 0;
        }
        .img-list ul::after{
            clear: both;
            content: &#39;&#39;;
            display: table;
        }
        .img-list ul li{
            float: left;
            margin: 0 10px;
            padding: 6px;
        }
        .img-list img{
            border: 2px solid transparent;
        }
        .img-list img.active{
            border: 2px solid red;
        }
        .big-box{
            position: absolute;
            top: 0;
            left: 100%;
            margin-left: 2px;
            border: 1px solid #cccccc;
            width: 500px;
            height: 500px;
            overflow: hidden;
            display: none;
        }
        .big-box img{
            position: absolute;
            top: 0;
            left: 0;
        }

    </style>
</head>
<body>
    <!-- 布局-->
    <div><!-- 容器-->
        <div><!-- 小图片容器-->
            <img src="../img/magnifier/m1.jpg" alt=""/>
            <div></div><!-- 鼠标选中框-->
            <div></div><!-- 鼠标悬浮位置-->
        </div>
        <div><!-- 图片列表-->
            <ul>
                <li><img src="../img/magnifier/s1.jpg" alt="" data-small="../img/magnifier/m1.jpg"
                         data-big="../img/magnifier/b1.jpg"/></li>
                <li><img src="../img/magnifier/s2.jpg" alt="" data-small="../img/magnifier/m2.jpg"
                         data-big="../img/magnifier/b2.jpg"/></li>
                <li><img src="../img/magnifier/s3.jpg" alt="" data-small="../img/magnifier/m3.jpg"
                         data-big="../img/magnifier/b3.jpg"/></li>
                <li><img src="../img/magnifier/s4.jpg" alt="" data-small="../img/magnifier/m4.jpg"
                         data-big="../img/magnifier/b4.jpg"/></li>
                <li><img src="../img/magnifier/s5.jpg" alt="" data-small="../img/magnifier/m5.jpg"
                         data-big="../img/magnifier/b5.jpg"/></li>
            </ul>
        </div>
        <div><!-- 放大镜-->
            <img src="../img/magnifier/b1.jpg" alt=""/>
        </div>
    </div>

    <script>
        //获取要操作的元素
        var smallbox = $(&#39;.small-box .mask&#39;);
        var smallimg = $(&#39;.small-box img&#39;);
        var square = $(&#39;.square&#39;);
        var bigbox = $(&#39;.big-box&#39;);
        var bigimg = $(&#39;.big-box img&#39;);
        var imgs = $all(&#39;.img-list img&#39;);

        //鼠标经过图片列表显示被选中，实现图片切换
        for(var i = 0; i < imgs.length; i++){
            imgs[i].onmouseover = function(){
                for(var j = 0; j < imgs.length; j++){
                    imgs[j].className = &#39;&#39;;
                }
                this.className = &#39;active&#39;;

                //改变对应的图片链接
                smallimg.src = this.getAttribute(&#39;data-small&#39;);
                bigimg.src = this.getAttribute(&#39;data-big&#39;);
            };
        }

        //鼠标移入放大器显示并设置选中框的大小
        smallbox.onmouseover = function(){
            square.style.display = &#39;block&#39;;
            bigbox.style.display = &#39;block&#39;;
            //位置w/smallimg.w = bigbox.w/bigimg.w
            square.style.width = bigbox.offsetWidth * smallimg.offsetWidth/bigimg.offsetWidth + &#39;px&#39;;
            square.style.height = bigbox.offsetHeight * smallimg.offsetHeight/bigimg.offsetHeight + &#39;px&#39;;
        };
        //鼠标移出放大器隐藏
        smallbox.onmouseout = function(){
            square.style.display = &#39;none&#39;;
            bigbox.style.display = &#39;none&#39;;
        };

        //放大器移动
        //获取鼠标的位置
        smallbox.onmousemove = function(ev){
            var oEvent = ev || event;
            var x = oEvent.offsetX - square.offsetWidth/2;
            var y = oEvent.offsetY - square.offsetHeight/2;

            if(x < 0){
                x = 0;
            }
            if(x > smallbox.offsetWidth - square.offsetWidth){
                x = smallbox.offsetWidth - square.offsetWidth;
            }
            if(y < 0){
                y = 0;
            }
            if(y > smallbox.offsetHeight - square.offsetHeight){
                y = smallbox.offsetHeight - square.offsetHeight;
            }

            //给选中框定位
            square.style.left = x + &#39;px&#39;;
            square.style.top = y + &#39;px&#39;;

            //给放大器定位  x/? = smallimg.w/bigimg.w
            bigimg.style.top = -y * bigimg.offsetWidth/smallimg.offsetWidth + &#39;px&#39;;
            bigimg.style.left = -x * bigimg.offsetHeight/smallimg.offsetHeight + &#39;px&#39;;

        };

        //通过名称查找某个元素
        function $(name){
            return document.querySelector(name);
        }
        //通过名称查找相同的一组数据
        function $all(name){
            return document.querySelectorAll(name);
        }
    </script>
</body>
</html>

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Summary:

The magnifying glass effect is completed here. I believe that my friends have their own understanding and understanding of this. I hope it will be helpful to your work!

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