js弹出提示框（js实现弹出一个对话框）

来源：引流技巧编辑：引流技巧时间：2026-04-30

>1.点击弹出框，状态框和遮挡层（背景变灰）就会显示出来 display：block；

2.点击关闭按钮，模态框和遮挡层就会隐藏起来 display：none;

3.在页面中拖拽的原理：鼠标按下并且移动，之后松开鼠标

4.触发事件是鼠标按下mousedown，鼠标移动mousemove，鼠标松开mouseup

5.推拽过程：鼠标移动过程中，获得最新的值赋给模态框的left和top值，这样模态框就可以跟着鼠标走了

6.鼠标按下出发的事件源是最上面一行，就是id为title

7.鼠标的坐标减去鼠标在盒子内的坐标，才是真正模态框的位置

8.鼠标按下，我们要得到鼠标在盒子的坐标

9.鼠标移动，就让模态框的坐标设置为：鼠标坐标减去盒子坐标即可，注意移动事件写到按下事件里面

10.鼠标松开，就是停止拖拽，就是可以让鼠标移动事件解除

代码

<!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> .login-header { width: 100%; text-align: center; height: 30px; font-size: 24px; line-height: 30px; } * { padding: 0; margin: 0; } .login { display: none; width: 512px; height: 280px; position: fixed; border: #ebebeb solid 1px; left: 50%; top: 50%; background: #ffffff; box-shadow: 0px 0px 20px #ddd; z-index: 9999; transform: translate(-50%, -50%); } .login-title { width: 100%; margin: 10px 0px 0px 0px; text-align: center; line-height: 40px; height: 40px; font-size: 18px; position: relative; cursor: move; } .login-input-content { margin-top: 20px; } .login-button { width: 50%; margin: 30px auto 0px auto; line-height: 40px; font-size: 14px; border: #ebebeb 1px solid; text-align: center; } .login-bg { display: none; width: 100%; height: 100%; position: fixed; top: 0px; left: 0px; background: rgba(0, 0, 0, .3); } a { text-decoration: none; color: #000000; } .login-button a { display: block; } .login-input input.list-input { float: left; line-height: 35px; height: 35px; width: 350px; border: #ebebeb 1px solid; text-indent: 5px; } .login-input { overflow: hidden; margin: 0px 0px 20px 0px; } .login-input label { float: left; width: 90px; padding-right: 10px; text-align: right; line-height: 35px; height: 35px; font-size: 14px; } .login-title span { position: absolute; font-size: 12px; right: -20px; top: -30px; background: #ffffff; border: #ebebeb solid 1px; width: 40px; height: 40px; border-radius: 20px; } </style></head><body> <div class=\"login-header\"><a id=\"link\" href=\"javascript:;\">点击，弹出登录框</a></div> <div id=\"login\" class=\"login\"> <div id=\"title\" class=\"login-title\">登录会员 <span><a id=\"closeBtn\" href=\"javascript:void(0);\" class=\"close-login\">关闭</a></span> </div> <div class=\"login-input-content\"> <div class=\"login-input\"> <label>用户名：</label> <input type=\"text\" placeholder=\"请输入用户名\" name=\"info[username]\" id=\"username\" class=\"list-input\"> </div> <div class=\"login-input\"> <label>登录密码：</label> <input type=\"password\" placeholder=\"请输入登录密码\" name=\"info[password]\" id=\"password\" class=\"list-input\"> </div> </div> <div id=\"loginBtn\" class=\"login-button\"><a href=\"javascript:void(0);\" id=\"login-button-submit\">登录会员</a></div> </div>  <div id=\"bg\" class=\"login-bg\"></div> <script> var link = document.querySelector(\'#link\'); //获取我们鼠标点击的对象 var login = document.querySelector(\'.login\'); //获得弹出框元素 var mask = document.querySelector(\'#bg\'); var closeBtn = document.querySelector(\'#closeBtn\'); link.addEventListener(\'click\', function() { login.style.display = \'block\'; mask.style.display = \'block\'; }) closeBtn.addEventListener(\'click\', function() { login.style.display = \'none\'; mask.style.display = \'none\'; }) var title = document.querySelector(\'#title\'); title.addEventListener(\'mousedown\', function(e) { var x = e.pageX - login.offsetLeft; var y = e.pageY - login.offsetTop; console.log(y); document.addEventListener(\'mousemove\', move) function move(e) { login.style.left = e.pageX - x + \'px\'; login.style.top = e.pageY - y + \'px\'; } document.addEventListener(\'mouseup\', function() { document.removeEventListener(\'mousemove\', move); }) }) </script></body></html>

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