<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
<style>
div {
200px;
height: 200px;
background-color: red;
position: absolute;
cursor: move;
}
* {
margin: 0;
padding: 0;
}
</style>
</head>
<body>
<div>dsgsad</div>
<div>dsgsad</div>
<div>dsgsad</div>
<div>dsgsad</div>
</body>
<script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
<script>
$('div').on('mousedown', function(e) { //鼠标按下
$(document).on('mousemove', (e) => {//鼠标移动
let left = e.clientX - $(this).width() / 2//计算元素left值
let top = e.clientY - $(this).height() / 2//计算元素top值
top = suan(top, 0, $(document).innerHeight() - $(this).height())//调用封装的方法
left = suan(left, 0,$(document).innerWidth() - $(this).width())//调用封装的方法
$(this).css({ //给盒子设置坐标
left,
top
})
e.preventDefault();
})
$(document).on('mouseup', (e) => {//鼠标抬起
$(document).off('mousemove')//移除鼠标移动事件
})
})
function suan(o, min, max) { //重复封装
o < min ? o = min : o > max ? o = max : ''//限制出界
return o
}
</script>
</html>