JS实现鼠标按下拖拽效果

时间:2020-07-23 York_Ice 人气:0

本文着重为大家仔细讲解了JS实现鼠标按下拖拽效果，文中代码实例讲解的非常细致，希望能够帮助到您，欢迎大家阅读和收藏

原生JS实现鼠标按下拖拽效果，供大家参考，具体内容如下

<!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>鼠标拖动</title>
 <style type="text/css">
 body {
  margin: 0;
 }

 div {
  width: 200px;
  height: 200px;
  position: absolute;
  background-color: pink;
 }
 </style>
</head>

<body>

 <div onmousedown="downDiv(this)" onmousemove="moveDiv(this)" onmouseup="upDiv(this)">

 </div>



 <script>
 //定义变量储存div的宽高
 var obj_w, obj_h;
 //定义一个变量判断是否执行移动函数
 var mouseDown = false;

 //鼠标按下函数
 function downDiv(obj) {
  //获取div的宽高
  obj_w = obj.offsetWidth;
  obj_h = obj.offsetHeight;
  //鼠标
  var e = event || window.event;
  //e.clientX/Y 是获取鼠标相对浏览器的位置；将div中心自动居中到鼠标
  obj.style.left = (e.clientX - obj_w / 2) + "px";
  obj.style.top = (e.clientY - obj_h / 2) + "px";
  console.log(obj.style.left, obj.style.top)
  //按下时为ture,松开时为false，以判断是否执行执行mouveDiv
  mouseDown = true;

 }

 //鼠标移动函数
 function moveDiv(obj) {
  obj_w = obj.offsetWidth;
  obj_h = obj.offsetHeight;
  var e = event || window.event;
  console.log(e.clientX, e.clientY);
  console.log(obj_w, obj_h);
  if (mouseDown) {
  obj.style.left = (e.clientX - obj_w / 2) + "px";
  obj.style.top = (e.clientY - obj_h / 2) + "px";
  console.log(obj.style.left, obj.style.top)
  }

 }

 //鼠标松开函数
 function upDiv(obj) {
  mouseDown = false;
 }

 </script>
</body>

</html>

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