实现鼠标左键拖拽效果的两种方式：
方式一：
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
.move {
width: 100px;
height: 100px;
background: red;
border-radius: 50%;
position:absolute;
left:0;
top:0;
}
</style>
</head>
<body>
<div>
</div>
<script>
//制作一个鼠标左键拖拽效果
var div = document.getElementsByClassName("move")[0];
var style = window.getComputedStyle(div);
var divLeft = parseFloat(style.left);
var divTop = parseFloat(style.top);
div.onmousedown = function(e){
if(e.button !== 0){
return ;//不是鼠标左键，return
}
window.onmousemove = function(e){
divLeft += e.movementX;//距上次鼠标位置的X长度
divTop += e.movementY;//距上次鼠标位置的Y长度
div.style.left = divLeft + "px";
div.style.top = divTop + "px";
}
window.onmouseup = window.onmouseleave = function(){
if(e.button === 0){//鼠标左键
window.onmousemove = null;
}
}
}
</script>
</body>
</html>
方式二：
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
.move {
width: 100px;
height: 100px;
background: red;
border-radius: 50%;
position:absolute;
left:0;
top:0;
}
</style>
</head>
<body>
<div>
</div>
<script>
//制作一个鼠标左键拖拽效果
var div = document.getElementsByClassName("move")[0];
var style = window.getComputedStyle(div);
div.onmousedown = function(e){
if(e.button !== 0){
return ;//不是鼠标左键，return
}
var divLeft = parseFloat(style.left);
var divTop = parseFloat(style.top);
var divPageX = e.pageX;
var divPageY = e.pageY;
window.onmousemove = function(e){
var disX = e.pageX - divPageX;
var disY = e.pageY - divPageY;
div.style.left = divLeft + disX + "px";
div.style.top = divTop + disY + "px";
}
window.onmouseup = window.onmouseleave = function(){
if(e.button === 0){//鼠标左键
window.onmousemove = null;
}
}
}
</script>
</body>
</html>
