本文实例为大家分享了JS实现拖拽功能的具体代码，供大家参考，具体内容如下
拖拽的原理：三个事件 onmousedown、onmousemove、onmousemove
1、鼠标按下，触发onmousedown，获取鼠标坐标x,y，获取元素坐标x,y
通过event.clientX、event.clientY获取鼠标位置的坐标
let x = e.clientX - box.offsetLeft; //鼠标点击坐标距离盒子左边缘的距离 let y = e.clientY - box.offsetTop; //鼠标点击坐标距离盒子上边缘的距离
2、设置元素left、top值，（元素要设置position:absolute）
box.style.left = ev.clientX - x + \'px\'; box.style.top = ev.clientY - y + \'px\';
3、放开鼠标取消dom事件
下面是详细代码：我只开了横向移动
<!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>
#box {
width: 100px;
height: 100px;
background: red;
position: absolute
}
</style>
</head>
<body style=\"position: relative;overflow: hidden;\">
<div id=\"box\">
</div>
<script>
window.onload = function () {
let box = document.getElementById(\'box\')
box.onmousedown = function (ev) {
let e = ev || event;
let x = e.clientX - box.offsetLeft; //鼠标点击坐标距离盒子左边缘的距离
let y = e.clientY - box.offsetTop; //鼠标点击坐标距离盒子上边缘的距离
document.onmousemove = function (ev) {
let e = ev || event;
box.style.left = ev.clientX - x + \'px\';
box.style.top = ev.clientY - y + \'px\';
let bodyScreenX = ev.screenX
let bodyClientWidth = document.body.clientWidth
document.onmouseup = function (ev) {
if (ev.clientX - x < 0) {
box.style.left = 0
} else if (bodyScreenX > bodyClientWidth) {
box.style.right = 0
box.style.left = bodyClientWidth - 100 + \'px\'
}
document.onmousemove = null;
document.onmouseup = null;
}
}
}
}
</script>
</body>
</html>
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。
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