原生js实现拼图效果

//执行初始函数init();function init() {    //创建一个碎片容器    var frag = document.createDocumentFragment();    document.body.style.margin = "0px";    //创建左侧图片容器    var ul=createE("ul",{        width: "260px",        height: "400px",        backgroundImage: "url(./img/3.jpg)",        borderRight: "1px solid #000",        borderBottom: "1px solid #000",        listStyle: "none",        padding: "0px",        margin: "0px",        opacity: ".3",        position: "absolute"    })    //创建li,显示图片中的边框    var li=createE("li",{        width: "51px",        height: "79px",        borderLeft: "1px solid #000",        borderTop: "1px solid #000",        padding: "0px",        margin: "0px",        float: "left"    })    //循环，将li复制插入到ul中    for (i = 0; i < 25; i++) {        ul.appendChild(li.cloneNode(false));    }    //将ul插入到碎片容器中    frag.appendChild(ul);    //创建右侧图片容器,因为img要相对body定位，所以它的父容器不能有定位属性    var div=createE("div",{        width: "302px",        height: "302px",        border: "1px solid #000",        marginLeft: "400px"    })    //创建图片标签    for (var j = 0; j < 5; j++) {        for (var k = 0; k < 5; k++) {            var img=createE("img",{                width: "52px",                height: "80px",                position: "absolute",                left: Math.floor(Math.random() * 250) + 400 + "px",                top: Math.floor(Math.random() * 220) + "px"            })            img.src = "./img/img" + j + "-" + k + ".jpg";            //图片侦听mouseHandler事件            img.addEventListener("mousedown", mouseHandler);            div.appendChild(img);        }    }    //将div插入到碎片容器中，再将frag插入到body中    frag.appendChild(div);    document.body.appendChild(frag);}//鼠标事件function mouseHandler(e) {    switch (e.type) {        case "mousedown":            //清除点击后移动图片的默认效果            e.preventDefault();            console.log(this.src.match(/img//img(.*)/.jpg/))            //获取到图片路径中的数字，计算图片正确的位置坐标            var imgSrc = this.src.match(/img//img(.*)/.jpg/)[1].split("-");            var rightL=imgSrc[1]*52;            var rightTop=imgSrc[0]*80;            //如果图片正确放入，直接跳出            if (this.style.left===rightL+"px" && this.style.top===rightTop+"px") return;            //将当前图片的z-index设为最大            this.style.zIndex = "999";            //将e.offsetX、e.offsetY、当前点击图片对象存入到document中            document.x = e.offsetX;            document.y = e.offsetY;            document.elem = this;            document.rightL=rightL;            document.rightTop=rightTop;            //document侦听mousemove事件和mouseup事件            document.addEventListener("mousemove", mouseHandler);            document.addEventListener("mouseup", mouseHandler);            break;        case "mousemove":            //自动吸附的距离大小            var gap = 20;            //设置当前的图片跟着鼠标移动而移动            let x=e.clientX - this.x;            let y=e.clientY - this.y;            this.elem.style.left = x + "px";            this.elem.style.top = y + "px";            //如果当前图片的位置坐标在一定范围内，则让它自动吸附            if (x>=this.rightL-gap &&x<=this.rightL+gap&&                y>=this.rightTop-gap &&y<=this.rightTop+gap) {                this.elem.style.left = this.rightL + "px";                this.elem.style.top = this.rightTop + "px";            }            break;        case "mouseup":            //鼠标松开的时候，将当前图片的z-index改小            this.elem.style.zIndex = "10";            //鼠标松开后，移除document的mousemove和mouseup事件,清空数据，防止内容泄露            this.removeEventListener("mousemove", mouseHandler);            this.removeEventListener("mouseup", mouseHandler);            this.elem=null;            break;    }}//创建标签function createE(elem,styleData){    var elem=document.createElement(elem);    for(var prep in styleData){        elem.style[prep]=styleData[prep];    }    return elem;}