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Js使用面向对象和面向过程的方法实现拖拽物体的效果

1.面向过程的拖拽实现代码：

<!DOCTYPE html>
<html>
<head>
    <title>drag Div</title>
    <style type="text/css">
        #div1{width: 100px;height: 100px;background: red;position: absolute;}
    </style>
    <script type="text/javascript">
        window.onload=function(){
            var oDiv=document.getElementById('div1');
            var disX=0;
            var disY=0;
            oDiv.onmousedown=function(ev){
                var oEvent=ev||event;
                disX=oEvent.clientX-oDiv.offsetLeft;
                disY=oEvent.clientY-oDiv.offsetTop;
                document.onmousemove=function(ev){
                var oEvent=ev||event;
                var l=oEvent.clientX-disX;
                var t=oEvent.clientY-disY;
                if (l<0)
                 {l=0;}
                else if(l>document.documentElement.clientWidth-oDiv.offsetWidth){
                    l=document.documentElement.clientWidth-oDiv.offsetWidth;
                }
                    if (t<0)
                 {t=0;}
                else if(t>document.documentElement.clientHeight-oDiv.offsetHeight){
                    l=document.documentElement.clientHeight-oDiv.offsetHeight;
                }

                oDiv.style.left=l+'px';
                oDiv.style.top=t+'px';
            };
            document.onmouseup=function(){
                document.onmousemove=null;
                document.onmouseup=null;
            }
        };

        return false;
        
    };
    </script>
</head>
<body>
    <div id="div1"></div>
</body>
</html>

2.面向对象的实现方法，只用新建对象，可以实现多个div的拖拽运动

<!DOCTYPE html>
<html>
<head>
    <title>drag Div</title>
    <style type="text/css">
        #div1{width: 100px;height: 100px;background: red;position: absolute;}
        #div2{width: 100px;height: 100px;background: yellow;position: absolute;}
    </style>
    <script type="text/javascript">
    window.onload=function(){
        new Drag('div1');
        new Drag('div2');
    }

        function Drag(id){
            var _this=this;
            this.disX=0;
            this.dixY=0;
            this.oDiv=document.getElementById(id);
            this.oDiv.onmousedown=function()
            {
                _this.fnDown();
            };

        return false;
        
    }
Drag.prototype.fnDown=function(ev){
                var _this=this;
                var oEvent=ev||event;
                this.disX=oEvent.clientX-this.oDiv.offsetLeft;
                this.disY=oEvent.clientY-this.oDiv.offsetTop;
                document.onmousemove=function(){
                    _this.fnMove();
                };
            document.onmouseup=function(){
                _this.fnUp();
            };
        };
Drag.prototype.fnMove=function(ev){
                var oEvent=ev||event;
                var l=oEvent.clientX-this.disX;
                var t=oEvent.clientY-this.disY;
                if (l<0)
                 {l=0;}
                else if(l>document.documentElement.clientWidth-this.oDiv.offsetWidth){
                    l=document.documentElement.clientWidth-this.oDiv.offsetWidth;
                }
                    if (t<0)
                 {t=0;}
                else if(t>document.documentElement.clientHeight-this.oDiv.offsetHeight){
                    l=document.documentElement.clientHeight-this.oDiv.offsetHeight;
                }

                this.oDiv.style.left=l+'px';
                this.oDiv.style.top=t+'px';
            };
Drag.prototype.fnUp=function(){
                document.onmousemove=null;
                document.onmouseup=null;
            };
    </script>
</head>
<body>
    <div id="div1"></div>
    <div id="div2"></div>
</body>
</html>

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原文地址：https://www.cnblogs.com/cheryshi/p/8494236.html