JS+DIV实现拖动效果

时间:2020-05-17 geekzsp 人气:0

本文实例为大家分享了JS+DIV实现拖动效果的具体代码，供大家参考，具体内容如下

效果图

思路

代码

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
</head>
<body>
<div id="main" style="background-color: aqua;width: 100px;height: 100px;position: absolute;left: 50px;top: 50px">
  <div id="title" style="height: 10px;width:100%;background-color: antiquewhite;position: absolute;left: 0px;top: 0px"></div>
  <div class="box"></div>
</div>
<script>

  var startx;
  var starty;
  var startLeft;
  var startTop;
  var titleDiv=document.getElementById("title");
  var mainDiv=document.getElementById("main");
  var isDown=false;
//  鼠标按下
  function movedown(e){
    e=e?e:window.event;
    isDown=true;
    startx=e.clientX;
    starty=e.clientY;
    startLeft=parseInt(mainDiv.style.left);
    startTop=parseInt(mainDiv.style.top);
  }
//  鼠标移动
  function move(e){
    e=e?e:window.event;
    if(isDown) {
      mainDiv.style.left = e.clientX - (startx - startLeft)+"px";
      mainDiv.style.top = e.clientY - (starty - startTop)+"px";
    }
  }
//  鼠标松开
  function moveup(){
    isDown=false;
  }
  titleDiv.οnmοusedοwn=movedown;
  titleDiv.οnmοusemοve=move;
  titleDiv.οnmοuseup=moveup;
</script>
</body>
</html>

优化(封装，以及解决拖动问题（事件捕获）)

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
</head>
<body>
<div id="main" style="background-color: aqua;width: 100px;height: 100px;position: absolute;left: 50px;top: 50px">
  <div id="title"
     style="height: 10px;width:100%;background-color: antiquewhite;position: absolute;left: 0px;top: 0px"></div>
  <div class="box"></div>
</div>
<script>


  function Mover(title) {
    this.obj = title;
    this.startx = 0;
    this.starty;
    this.startLeft;
    this.startTop;
    this.mainDiv = title.parentNode;
    var that = this;
    this.isDown = false;
    this.movedown = function (e) {
      e = e ? e : window.event;
      if (!window.captureEvents) {
        this.setCapture();
      } //事件捕获仅支持ie
//      函数功能：该函数在属于当前线程的指定窗口里设置鼠标捕获。一旦窗口捕获了鼠标，
//      所有鼠标输入都针对该窗口，无论光标是否在窗口的边界内。同一时刻只能有一个窗口捕获鼠标。
//      如果鼠标光标在另一个线程创建的窗口上，只有当鼠标键按下时系统才将鼠标输入指向指定的窗口。
//      非ie浏览器 需要在document上设置事件
      that.isDown = true;
      that.startx = e.clientX;
      that.starty = e.clientY;

      that.startLeft = parseInt(that.mainDiv.style.left);
      that.startTop = parseInt(that.mainDiv.style.top);
    }
    this.move = function (e) {
      e = e ? e : window.event;
      if (that.isDown) {
        that.mainDiv.style.left = e.clientX - (that.startx - that.startLeft) + "px";
        that.mainDiv.style.top = e.clientY - (that.starty - that.startTop) + "px";
      }
    }
    this.moveup = function () {
      that.isDown = false;
      if (!window.captureEvents) {
        this.releaseCapture();
      } //事件捕获仅支持ie
    }
    this.obj.onmousedown = this.movedown;
    this.obj.onmousemove = this.move;
    this.obj.onmouseup = this.moveup;

    //非ie浏览器
    document.addEventListener("mousemove", this.move, true);
  }
  var mover = new Mover(document.getElementById("title"));


  //写两个是为了解决 ie 和非ie 浏览器关于事件捕获 的兼容性问题


</script>
</body>
</html>

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