拖拽初体验

1. 基本功能实现

<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
  <style>
    * {
      margin: 0;
      padding: 0;
    }

    div {
       200px;
      height: 200px;
      border: 1px solid red;
      font-size: 30px;
      color: #000;
      background-color: #ccc;
    }
  </style>
</head>

<body>

  <div>   hello  </div>

  <script>

    var objLeft, objTop, pointX, pointY;
    var flag = false;

    $('div').style.cssText = 'position:relative;left:0px;top:0px;';

    $('div').onmousedown = function (e) {
      var e = e || window.e;
      pointX = e.clientX;
      pointY = e.clientY;
      objLeft = parseFloat($('div').style.left) - 0;
      objTop = parseFloat($('div').style.top) - 0;
      flag = true;
    }
    document.onmousemove = function (e) {
      var e = e || window.e;
      if (flag) {
        $('div').style.left = e.clientX - pointX + objLeft + 'px';
        $('div').style.top = e.clientY - pointY + objTop + 'px';
      }
    }
    document.onmouseup = function () {
      flag = false;
    }

    function $(select) {
      return document.querySelector(select);
    }
  </script>


</body>

</html>

View Code

1.1 另一个角度实现拖拽

<!docType html>
<html>

<head>
    <style type="text/css">
        #drag {
            border: 1px solid blue;
            width: 100px;
            height: 100px;
            position: absolute;
        }
    </style>
</head>

<body>
    <input id="x" />
    <input id="y" />
    <div id="drag">
        <input value="x" />
        <input value="y" />
    </div>

    <script>
        var drag = document.getElementById('drag');
        var inputX = document.getElementById('x');
        var inputY = document.getElementById('y');
        if (document.attachEvent) {
            drag.attachEvent('onmousedown', dragHandle);
        } else {
            drag.addEventListener('mousedown', dragHandle, false);
        }

        function dragHandle(event) {
            var event = event || window.event;
            var startX = drag.offsetLeft;
            var startY = drag.offsetTop;
            var mouseX = event.clientX;
            var mouseY = event.clientY;
            var deltaX = mouseX - startX;
            var deltaY = mouseY - startY;
            if (document.attachEvent) {
                drag.attachEvent('onmousemove', moveHandle);
                drag.attachEvent('onmouseup', upHandle);
                drag.attachEvent('onlosecapture', upHandle);
                drag.setCapture();
            } else {
                document.addEventListener('mousemove', moveHandle, true);
                document.addEventListener('mouseup', upHandle, true);
            }

            function moveHandle(event) {
                var event = event || window.event;
                drag.style.left = (event.clientX - deltaX) + "px";
                drag.style.top = (event.clientY - deltaY) + "px";
                inputX.value = drag.style.left;
                inputY.value = drag.style.top;
            }

            function upHandle() {
                if (document.attachEvent) {
                    drag.detachEvent('onmousemove', moveHandle);
                    drag.detachEvent('onmouseup', upHandle);
                    drag.detachEvent('onlosecapture', upHandle);
                    drag.releaseCapture();
                } else {
                    document.removeEventListener('mousemove', moveHandle, true);
                    document.removeEventListener('mouseup', upHandle, true);
                }
            }

        }
    </script>
</body>

</html>

View Code

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拖拽初体验