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JavaScript implements draggable layer Div instance_javascript skills

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May 16, 2016 pm 03:47 PM

divjavascriptdrag

The example in this article describes how to implement a draggable layer Div using JavaScript. Share it with everyone for your reference. The details are as follows:

This is a perfect JS dragging effect. The JavaScript dragging layer code with a tail has been optimized and corrected many times. The method of copying nodes is good and worth learning for JS enthusiasts. At the same time, the code has been modified for dragging elements. Added the issue that the ondblclick event is invalid. It is compatible with multiple browsers and can be run and used by copying the code.

The operation effect is as shown below:

The specific code is as follows:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
<style type="text/css">
*{ margin:0; padding:0;} .div{ width:100px; height:100px; position:absolute;left:100px; top:100px; background:#ccc;}
</style>
</head>
<body>
  <div class="div">
  </div>
  <script type="text/javascript">
   var div = document.getElementsByTagName('div')[0];
   var zIndex = 6;
   drag(div);
   div.ondblclick = function() {
    alert("ok");
   };
   function drag(oDrag) {
    var disX = dixY = 0;
    oDrag.onmousedown = function(event) {
     var event = event || window.event;
     disX = event.clientX - this.offsetLeft;
     disY = event.clientY - this.offsetTop;
     var oTemp = this.cloneNode(true);
     document.body.appendChild(oTemp);
     document.onmousemove = function(event) {
      var event = event || window.event;
      var iL = event.clientX - disX;
      var iT = event.clientY - disY;
      var maxL = document.documentElement.clientWidth - oDrag.offsetWidth;
      var maxT = document.documentElement.clientHeight - oDrag.offsetHeight;
      iL <= 0 && (iL = 0);
      iT <= 0 && (iT = 0);
      iL >= maxL && (iL = maxL);
      iT >= maxT && (iT = maxT);
      oTemp.style.zIndex = zIndex++;
      oTemp.style.opacity = "0.5";
      oTemp.style.filter = "alpha(opacity=50)";
      oTemp.style.left = iL + "px";
      oTemp.style.top = iT + "px";
      return false;
     };
     document.onmouseup = function() {
      document.onmousemove = null;
      document.onmouseup = null;
      oDrag.style.opacity = oTemp.style.opacity;
      var arr = {
       left: oTemp.offsetLeft,
       top: oTemp.offsetTop
      };
      oDrag.style.zIndex = oTemp.style.zIndex;
      oAnimate(oDrag, arr, 300,
      function() {
       document.body.removeChild(oTemp);
      });
      oDrag.releaseCapture && oDrag.releaseCapture()
     };
     this.setCapture && this.setCapture();
     return false
    }
   }
   function oAnimate(obj, params, time, handler) {
    var node = typeof obj == "string" &#63; $(obj) : obj;
    var _style = node.currentStyle &#63; node.currentStyle: window.getComputedStyle(node, null);
    var handleFlag = true;
    for (var p in params) { (function() {
      var n = p;
      if (n == "left" || n == "top") {
       var _old = parseInt(_style[n]);
       var _new = parseInt(params[n]);
       var _length = 0,
       _tt = 10;
       if (!isNaN(_old)) {
        var count = _old;
        var length = _old <= _new &#63; (_new - _old) : (_old - _new);
        var speed = length / time * _tt;
        var flag = 0;
        var anim = setInterval(function() {
         node.style[n] = count + "px";
         count = _old <= _new &#63; count + speed: count - speed;
         flag += _tt;
         if (flag >= time) {
          node.style[n] = _new + "px";
          clearInterval(anim);
          if (handleFlag) {
           handler();
           handleFlag = false;
          }
         }
        },
        _tt);
       }
      }
     })();
    }
   }
  </script>
 </body>
</html>

I hope this article will be helpful to everyone’s JavaScript programming design.

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