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                <div class="red" id="red_box"></div>


                        * {
            margin: 0;
            padding: 0;

        .red {
            width: 200px;
            height: 200px;
            position: absolute;
            top: 40%;
            left: 40%;
            background-color: red;


                        window.onload = function () {
            //鼠标按下onmousedown   鼠标弹起:onmouseup   鼠标移动onmousemove

            var red_box = document.getElementById("red_box");

            red_box.onmousedown = function (event) {
                event = event || window.event;
                var pagex = event.pageX || scroll().left + event.clientX;
                var pagey = event.pageY || scroll().top + event.clientY;
                var x = pagex - red_box.offsetLeft;
                var y = pagey - red_box.offsetTop;

                var red_l0 = red_box.offsetLeft
                var red_t0 = red_box.offsetTop

                document.onmousemove = function (event) {
                    event = event || window.event;
                    var origin_xx = event.pageX || scroll().left + event.clientX;
                    var origin_yy = event.pageY || scroll().top + event.clientY;

                    //二次操作鼠标位置  减去鼠标在盒子中的坐标
                    var xx = origin_xx - x;
                    var yy = origin_yy - y;
           = xx + "px";
           = yy + "px";

                    // window.getSelection ? window.getSelection().removeAllRanges() : document.selection.empty();

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