最短距离求错了,还待改正,先记录下来再说

<!DOCTYPE HTML>
<html lang="en-US">
<head>
<meta charset="UTF-8">
<title>可拖拽的照片墙</title>
<style type="text/css">
html body {
    margin:0;
}
#wrap {
    list-style:none;
    padding:0;
    margin:30px auto;
    width:670px;
    position:relative;
    zoom:1;
}
.clearfix:after {
    content:'';
    height:0;
    clear:both;
    display:block;
    visibility:hidden;
}
#wrap div{
    float:left;
    margin:10px;
    z-index:1;
    border:1px solid #fff;
}
#wrap div img{
    width:200px;
    height:150px;
    vertical-align:bottom;
}
#wrap div.active {
    border:1px dashed red;
}
</style>
</head>
<body>
<div id="wrap" class='clearfix'>
  <div><img src="http://pingfan1990.sinaapp.com/javacript/dargimg/1.jpg" /></div>
  <div><img src="http://pingfan1990.sinaapp.com/javacript/dargimg/2.jpg" /></div>
  <div><img src="http://pingfan1990.sinaapp.com/javacript/dargimg/3.jpg" /></div>
  <div><img src="http://pingfan1990.sinaapp.com/javacript/dargimg/4.jpg" /></div>
  <div><img src="http://pingfan1990.sinaapp.com/javacript/dargimg/5.jpg" /></div>
  <div><img src="http://pingfan1990.sinaapp.com/javacript/dargimg/6.jpg" /></div>
  <div><img src="http://pingfan1990.sinaapp.com/javacript/dargimg/7.jpg" /></div>
  <div><img src="http://pingfan1990.sinaapp.com/javacript/dargimg/8.jpg" /></div>
  <div><img src="http://pingfan1990.sinaapp.com/javacript/dargimg/9.jpg" /></div>
</div>
<script type="text/javascript">
var o=document.getElementById("wrap");
var arr=o.getElementsByTagName("div");
var ind=2;
for(var i=arr.length;i--;i>=0){
    arr[i].style.left=arr[i].offsetLeft+"px";
    arr[i].style.top=arr[i].offsetTop+"px";    
    arr[i].style.position="absolute";
    arr[i].style.margin=0;
    m(arr[i])    
}


//拖动和各种判断
function m(obj){
    var mind=999999;
    var num=-1;
    obj.onmousedown=function(e){
        var e=e||event;
        ind++;
        var aa=[obj.offsetLeft,obj.offsetTop];
        var disX=e.clientX-obj.offsetLeft;
        var disY=e.clientY-obj.offsetTop;
        this.style.zIndex=ind;
        
        
        document.onmousemove=function(e){
            var e=e||event;
            obj.style.left=e.clientX-disX+"px";
            obj.style.top=e.clientY-disY+"px";
            
            var s=siblings(obj);
            for(var i=0;i<s.length;i++){
                if(c(obj,s[i])){
                    
                    var dis=distance(obj,s[i]);    
                    if(mind>dis){
                        mind=dis;
                        num=i;
                    }
                    s[i].className="active";
                }else{
                    num=-1;
                    s[i].className="";
                }
            }
            
            
        }
        
        document.onmouseup=function(){
            exchangePosition(obj,siblings(obj)[num],aa);
            document.onmousemove=null;
            document.onmouseup=null;
            }
        
        return false;
    }
}





function exchangePosition(a,b,x){
    if(b){
        a.style.left=b.offsetLeft+"px";
        a.style.top=b.offsetTop+"px";
        b.style.left=x[0]+"px";
        b.style.top=x[1]+"px";
    }else{
        a.style.left=x[0]+"px";
        a.style.top=x[1]+"px";    
    }
}


//求两个Div之间的距离
function distance(x,y){
        var l=x.offsetLeft+x.offsetWidth/2;
        var t=x.offsetTop+x.offsetHeight/2;
        var ll=y.offsetLeft+y.offsetWidth/2;
        var tt=y.offsetTop+y.offsetHeight/2;
        
        var dis=Math.sqrt((l-ll)*(l-ll)+(t-tt)*(t-tt));
        return dis
        
}

//碰撞检测方法
function c(x,y){
    var l=x.offsetLeft;
    var r=l+x.offsetWidth;
    var t=x.offsetTop;
    var b=t+x.offsetHeight;
    
    var ll=y.offsetLeft;
    var rr=ll+y.offsetWidth;
    var tt=y.offsetTop;
    var bb=tt+y.offsetHeight;

    if(r<ll || b<tt || l>rr || t>bb){
        return false;
    }else{
        return true;
    }    
}


function siblings(obj){
    return preall(obj).concat(nextall(obj))
}

function preall(obj){
    var arr=[];
    var o=obj.previousSibling;
    while(o){
        if(o.nodeType==1){
            arr.unshift(o);
        }
        o=o.previousSibling;
    }
    return arr;
}

function nextall(obj){
    var arr=[];
    var o=obj.nextSibling;
    while(o){
        if(o.nodeType==1){
            arr.push(o);
        }
        o=o.nextSibling;
    }
    return arr;
    
}


</script>
原文地址:https://www.cnblogs.com/busicu/p/3966791.html