Native js implements draggable login box effect-JS Tutorial-php.cn

Home

Web Front-end

JS Tutorial

Native js implements draggable login box effect

高洛峰

Feb 08, 2017 pm 05:19 PM

实现原理

1.onmousemove事件触发时不断更新鼠标的pageXY改变位置，

登陆框的偏移量=鼠标当前位置-鼠标到登录框边框的距离

2.onmousedown鼠标摁下时触发事件获取鼠标到登陆框的距离，再设置true允许拖拽

3.onmouseup 鼠标弹起设置false停止拖拽

4.登录框居中显示公式：(可视区域宽高-登录框宽高)/2

5.当浏览器窗口大小变化时触发事件window.onresize 再更新登陆框居中显示

代码中有详细的注释

完整代码

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>demo</title>
<style>
body,h1,h2,h3,h4,h5,h6,hr,p,blockquote,dl,dt,dd,ul,ol,li,pre,form,fieldset,legend,button,input,textarea,th,td{margin:0;padding:0;}
body,button,input,select,textarea{font:12px/1.5 tahoma,arial,\5b8b\4f53;}
h1,h2,h3,h4,h5,h6{font-size:100%;}
address,cite,dfn,em,var{font-style:normal;}
code,kbd,pre,samp{font-family:courier new,courier,monospace;}
small{font-size:12px;}
ul,ol{list-style:none;}
a{text-decoration:none;}
a:hover{text-decoration:underline;}
sup{vertical-align:text-top;}
sub{vertical-align:text-bottom;}
legend{color:#000;}
fieldset,img{border:0;}
button,input,select,textarea{font-size:100%;}
table{border-collapse:collapse;border-spacing:0;}
.clear{clear: both;float: none;height: 0;overflow: hidden;}
/*p{font-size: 100px;}*/
#btn{width: 80px;
 height: 40px;
 background: #3b7ae3;
 margin:0 auto;
 display: block;
 cursor: pointer;
 border-style: none;
 color: #fff;
 font-size: 16px;}
#mask{
 background: #000;
 opacity: 0.75;
 filter: alpha(opacity=75);
 height: 1000px;
 width: 100%;
 position: absolute;
 left: 0;
 top: 0;
 z-index: 1000;
}
#login{position: absolute; top: 100px; left: 100px; width: 400px; height: auto; border:1px solid #d5d5d5; z-index: 1001; }
.title{position: relative;background-color: #f7f7f7; cursor: move; height: 50px; line-height: 50px; font-size: 16px; color: #333; padding-left:30px;}
.close{position: absolute; top:0; right: 10px; color: #ccc;}
.content{background: #fff; padding: 15px 20px;}
.user{margin-bottom: 15px;}
.password{margin-bottom: 15px;}
.pt{display: block;
 height: 38px;
 padding-left: 15px;
 border: 1px solid #ddd;
 transition: .3s;
 font-size: 14px;
 color: #666;
 width: 343px;
 }
.sm{display: block;
 height: 48px;
 border: 1px solid #ddd;
 transition: .3s;
 font-size: 16px;
 color: #666;
 width: 360px;
 background: #3b7ae3;
 color: #fff;}
</style> 
</head> 
<body>
 <!-- <div id="mask"></div> -->
 <button id="btn" href="">登录</button>
 <!-- <div class="login" id="login">
 <div class="title" id="title">登录百度账号<a href="#" class="close">x</a></div>
 <div class="content">
 <div class="user"><input class="pt" type="input" value="手机/邮箱/用户名"></div>
 <div class="password"><input class="pt" type="input" value="密码"></div>
 <div class="submit"><input class="sm" type="submit" value="登录"></div>
 </div>
 </div> -->
<script type="text/javascript">
 function b(){ 
 //创建遮罩层div并插入body
 var mask=document.createElement("div");
 mask.id="mask";
 mask.style.height=cheight+"px";
 //宽度直接用100%在样式里
 document.body.appendChild(mask);
 //创建登录层div并插入body
 var login=document.createElement("div");
 login.id="login";
 login.innerHTML=&#39;<div class="title" id="title">登录百度账号&#39;+&#39;<a href="#" class="close">x</a>&#39;+&#39;</div>&#39;+
 &#39;<div class="content">&#39;+&#39;<div class="user">&#39;+&#39;<input class="pt" type="input" value="手机/邮箱/用户名">&#39;+&#39;</div>&#39;+&#39;<div class="password">&#39;+&#39;<input class="pt" type="input" value="密码">&#39;+&#39;</div>&#39;+&#39;<div class="submit">&#39;+&#39;<input class="sm" type="submit" value="登录">&#39;+&#39;</div>&#39;+&#39;</div>&#39;;
 document.body.appendChild(login);
 //窗口可视区域宽度
 var cwidth= document.documentElement.clientWidth || document.body.clientWidth;
 //窗口可视区域高度
 var cheight= document.documentElement.clientHeight || document.body.clientHeight;
 //登录框宽度
 var lwidth=login.offsetWidth;
 //登录框高度
 var lheight=login.offsetHeight;
 //设置登录框的居中显示
 login.style.left=(cwidth-lwidth)/2+"px";
 login.style.top=(cheight-lheight)/2+"px";
 //设置遮罩层的高度
 mask.style.height=cheight+"px";
 //改变窗口大小后依然居中显示
 window.onresize=function(){
 if(document.compatMode=="CSS1Compat"){  
cwidth=document.documentElement.clientWidth;
cheight=document.documentElement.clientHeight;
 }else{  
  cwidth=document.body.clientWidth;
  cheight=document.body.clientHeight;
 }
 login.style.left=(cwidth-lwidth)/2+"px";
 login.style.top=(cheight-lheight)/2+"px";
 mask.style.height=cheight+"px";
 }
 //获取拖拽容器
 var title=document.getElementById("title");
 var isDraging=false;
 var mouseOffsetX;
 var mouseOffsetY;
 //鼠标按下事件
 title.onmousedown=function(e){
 var e=e||window.event;
 /*var el=e.srcElement;
 if(!el){
 el=e.target;//兼容火狐
 }*/
 //鼠标相对于登录框的位置
 mouseOffsetX=e.pageX-login.offsetLeft;
 mouseOffsetY=e.pageY-login.offsetTop;
 //鼠标摁下时为true
 isDraging=true;
 /*console.log(mouseOffsetY, mouseOffsetX)*/
 }
 //鼠标移动事件
 document.onmousemove=function(e){
 var e=e||window.event;
 //鼠标移动时的坐标
 var newMX=e.pageX;
 var newMY=e.pageY;
 //判断为true时可以拖拽
 if(isDraging===true){
 //登录框的偏移值=当前位置-鼠标到登录框的距离
 var loginL=newMX-mouseOffsetX;
 var loginT=newMY-mouseOffsetY;
 //如果left top值超过边缘时就让他等于边缘
 if(loginL<0){
 loginL=0;
 }else if(loginL>(cwidth-lwidth)){
 loginL=cwidth-lwidth;
 }
 if(loginT<0){
 loginT=0;
 }else if(loginT>(cheight-lheight)){
 loginT=cheight-lheight;
 }
 login.style.left=loginL+"px";
 login.style.top=loginT+"px";
 } 
 }
 //鼠标弹起时设置为不可拖拽
 document.onmouseup=function(){
 isDraging=false;
 }
 //点击X关闭登录框和弹出层
 var close=login.getElementsByClassName("close")[0];
 close.onclick=function(){
 document.body.removeChild(mask);
 document.body.removeChild(login);
 }
 }
 //点击登录弹出登录框和弹出层
 window.onload=function(){
 var btn=document.getElementById("btn");
 btn.onclick=function(){
 b();
 }
 }
</script> 
</body> 
</html>

以上就是本文的全部内容，希望本文的内容对大家的学习或者工作能带来一定的帮助，同时也希望多多支持PHP中文网！

更多原生js实现可拖动的登录框效果相关文章请关注PHP中文网！

Statement

The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Python vs. JavaScript: Community, Libraries, and ResourcesApr 15, 2025 am 12:16 AM

Python and JavaScript have their own advantages and disadvantages in terms of community, libraries and resources. 1) The Python community is friendly and suitable for beginners, but the front-end development resources are not as rich as JavaScript. 2) Python is powerful in data science and machine learning libraries, while JavaScript is better in front-end development libraries and frameworks. 3) Both have rich learning resources, but Python is suitable for starting with official documents, while JavaScript is better with MDNWebDocs. The choice should be based on project needs and personal interests.

From C/C to JavaScript: How It All WorksApr 14, 2025 am 12:05 AM

The shift from C/C to JavaScript requires adapting to dynamic typing, garbage collection and asynchronous programming. 1) C/C is a statically typed language that requires manual memory management, while JavaScript is dynamically typed and garbage collection is automatically processed. 2) C/C needs to be compiled into machine code, while JavaScript is an interpreted language. 3) JavaScript introduces concepts such as closures, prototype chains and Promise, which enhances flexibility and asynchronous programming capabilities.

JavaScript Engines: Comparing ImplementationsApr 13, 2025 am 12:05 AM

Different JavaScript engines have different effects when parsing and executing JavaScript code, because the implementation principles and optimization strategies of each engine differ. 1. Lexical analysis: convert source code into lexical unit. 2. Grammar analysis: Generate an abstract syntax tree. 3. Optimization and compilation: Generate machine code through the JIT compiler. 4. Execute: Run the machine code. V8 engine optimizes through instant compilation and hidden class, SpiderMonkey uses a type inference system, resulting in different performance performance on the same code.

Beyond the Browser: JavaScript in the Real WorldApr 12, 2025 am 12:06 AM

JavaScript's applications in the real world include server-side programming, mobile application development and Internet of Things control: 1. Server-side programming is realized through Node.js, suitable for high concurrent request processing. 2. Mobile application development is carried out through ReactNative and supports cross-platform deployment. 3. Used for IoT device control through Johnny-Five library, suitable for hardware interaction.

Building a Multi-Tenant SaaS Application with Next.js (Backend Integration)Apr 11, 2025 am 08:23 AM

I built a functional multi-tenant SaaS application (an EdTech app) with your everyday tech tool and you can do the same. First, what’s a multi-tenant SaaS application? Multi-tenant SaaS applications let you serve multiple customers from a sing

How to Build a Multi-Tenant SaaS Application with Next.js (Frontend Integration)Apr 11, 2025 am 08:22 AM

This article demonstrates frontend integration with a backend secured by Permit, building a functional EdTech SaaS application using Next.js. The frontend fetches user permissions to control UI visibility and ensures API requests adhere to role-base

JavaScript: Exploring the Versatility of a Web LanguageApr 11, 2025 am 12:01 AM

JavaScript is the core language of modern web development and is widely used for its diversity and flexibility. 1) Front-end development: build dynamic web pages and single-page applications through DOM operations and modern frameworks (such as React, Vue.js, Angular). 2) Server-side development: Node.js uses a non-blocking I/O model to handle high concurrency and real-time applications. 3) Mobile and desktop application development: cross-platform development is realized through ReactNative and Electron to improve development efficiency.

The Evolution of JavaScript: Current Trends and Future ProspectsApr 10, 2025 am 09:33 AM

The latest trends in JavaScript include the rise of TypeScript, the popularity of modern frameworks and libraries, and the application of WebAssembly. Future prospects cover more powerful type systems, the development of server-side JavaScript, the expansion of artificial intelligence and machine learning, and the potential of IoT and edge computing.

See all articles