鼠标拖拽

<!DOCTYPE HTML>
<html>
<head>
    <meta charset="utf-8">
    <title>无标题文档</title>
    <style>
        #div1 {
             200px;
            height: 200px;
            background: red;
            position: absolute;
        }
    </style>
    <script>
        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) {//可视区的宽度——div宽度
                        l = document.documentElement.clientWidth - oDiv.offsetWidth;
                    }
                    if (t < 0) {
                        t = 0;
                    }
                    else if (t > document.documentElement.clientHeight - oDiv.offsetHeight) {
                        t = 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>

div拖拽带框：
<!DOCTYPE HTML>
<html>
<head>
    <meta charset="utf-8">
    <title>无标题文档</title>
    <style>
        #div1 {
             100px;
            height: 100px;
            background: yellow;
            position: absolute;
        }

        .box {
            border: 1px dashed black;
            position: absolute;
        }
    </style>
    <script>
        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;

                var oBox = document.createElement('div');

                oBox.className = 'box';
                oBox.style.width = oDiv.offsetWidth - 2 + 'px';
                oBox.style.height = oDiv.offsetHeight - 2 + 'px';

                oBox.style.left = oDiv.offsetLeft + 'px';
                oBox.style.top = oDiv.offsetTop + 'px';

                document.body.appendChild(oBox);

                document.onmousemove = function (ev) {
                    var oEvent = ev || event;
                    var l = oEvent.clientX - disX;
                    var t = oEvent.clientY - disY;

                    oBox.style.left = l + 'px';
                    oBox.style.top = t + 'px';
                };

                document.onmouseup = function () {
                    document.onmousemove = null;
                    document.onmouseup = null;

                    oDiv.style.left = oBox.offsetLeft + 'px';
                    oDiv.style.top = oBox.offsetTop + 'px';

                    document.body.removeChild(oBox);
                };

                return false;  //chrome、ff、IE9
            };
        };
    </script>
</head>

<body>
<div id="div1"></div>
</body>
</html>
div拖拽吸附：

<!DOCTYPE HTML>
<html>
<head>
    <meta charset="utf-8">
    <title>无标题文档</title>
    <style>
        #div1 {
             100px;
            height: 100px;
            background: red;
            position: absolute;
        }

        #div2 {
             700px;
            height: 500px;
            background: #CCC;
            position: relative;
        }
    </style>
    <script>
        window.onload = function () {
            var oDiv = document.getElementById('div1');
            var oDiv2 = document.getElementById('div2');

            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 < 50) {
                        l = 0;
                    } else if (l > 550) {
                        l = 600;
                    }
                    else if (l > oDiv2.offsetWidth - oDiv.offsetWidth) {
                        l = oDiv2.offsetWidth - oDiv.offsetWidth;
                    }

                    if (t < 50) {
                        t = 0;
                    } else if (t > 350) {
                        t = 400;
                    }
                    else if (t > oDiv2.offsetHeight - oDiv.offsetHeight) {
                        t = oDiv2.offsetHeight - 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="div2">
    <div id="div1"></div>
</div>
</body>
</html>
 
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原文地址：https://www.cnblogs.com/theWayToAce/p/5305406.html