效果图：
代码如下：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>登录框鼠标拖拽效果</title>
<style type="text/css">
body {
background: url("https://timgsa.baidu.com/timg") no-repeat top center #ffffff;
background-size: 100%;
padding: 0;
margin: 0;
font-size: 12px;
font-family: "微软雅黑", sans-serif;
}
.ui-dialog {
width: 380px;
position: absolute;
z-index: 9000;
top: 100px;
left: 100px;
border: 1px solid #d5d5d5;
background-color: #ffffff;
/*display: none;*/
}
.ui-dialog-title {
height: 48px;
line-height: 48px;
padding-left: 20px;
color: #535353;
font-size: 16px;
background-color: #f5f5f5;
border-bottom: 1px solid #efefef;
cursor: move;
}
.ui-dialog-title-closebutton {
width: 16px;
height: 16px;
display: inline-block;
position: absolute;
right: 20px;
color: #000;
text-decoration: unset;
}
.ui-dialog-title-closebutton:hover {
color: #4ca8ff;
}
.ui-dialog-content {
padding: 15px 20px;
}
.ui-dialog-pt15 {
padding-top: 15px;
}
.ui-dialog-l40 {
height: 40px;
line-height: 40px;
text-align: right;
}
.ui-dialog-input {
width: 100%;
height: 40px;
margin: 0;
padding: 0;
border:1px solid #d5d5d5;
font-size: 16px;
color: #c1c1c1;
text-indent: 25px;
outline: none;
}
.ui-dialog-input-username {
background: url("images/input_username.png") no-repeat 2px;
}
.ui-dialog-input-password {
background: url("images/input_password.png") no-repeat 2px;
}
.ui-dialog-submit {
width: 100%;
height: 50px;
background: #3b7ae3;
border: none;
font-size: 16px;
color: #ffffff;
outline: none;
text-decoration: none;
display: block;
text-align: center;
line-height: 50px;
}
.ui-dialog-submit:hover {
background: #3f81b0;
}
.ui-mask {
width: 100%;
height: 100%;
background: #000;
opacity: 0.4;
position: absolute;
top: 0;
left: 0;
z-index: 8000;
display: none;
}
.link {
text-align: right;
line-height: 20px;
padding-right: 40px;
}
</style>
</head>
<body>
<div class="ui-dialog" id="dialog">
<div class="ui-dialog-title" id="dialogTitle">
登录
<!-- 右上角的关闭按钮 -->
<a href="javascript:hideDialog();" rel="external nofollow" class="ui-dialog-title-closebutton">X</a>
</div>
<div class="ui-dialog-content">
<div class="ui-dialog-l40 ui-dialog-pt15">
<input class="ui-dialog-input ui-dialog-input-username" type="input" placeholder="手机/邮箱/用户名" />
</div>
<div class="ui-dialog-l40 ui-dialog-pt15">
<input class="ui-dialog-input ui-dialog-input-password" type="input" placeholder="密码" />
</div>
<div class="ui-dialog-l40">
<a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" >忘记密码</a>
</div>
<div>
<a class="ui-dialog-submit" href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" >登录</a>
</div>
<div class="ui-dialog-l40">
<a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" >立即注册</a>
</div>
</div>
</div>
<div class="ui-mask" id="mask"></div>
<div class="link">
<a href="javascript:showDialog();" rel="external nofollow" style=" text-decoration: unset;color: #4ca8ff">登录</a>
</div>
<script type="text/javascript">
// 获取元素对象
function g(id) {
return document.getElementById(id);
}
// 自动居中函数 -- 登录浮层
// el {Element}
function autoCenter(el) {
// 获得可视区域的宽和高
var bodyW = document.documentElement.clientWidth;
var bodyH = document.documentElement.clientHeight;
// 获得元素 el 的宽和高
var elW = el.offsetWidth;
var elH = el.offsetHeight;
// 设置元素的 style 样式
el.style.left = (bodyW - elW) / 2 + 'px';
el.style.top = (bodyH - elH) / 2 + 'px';
}
// 扩展元素到整个可视区域 -- 遮罩层
// el {Element}
function fillToBody(el) {
// 将元素的宽和高设置的和可视区域一样
el.style.width = document.documentElement.clientWidth + 'px';
el.style.height = document.documentElement.clientHeight + 'px';
}
// 定义全局变量
var mouseOffsetX = 0;
var mouseOffsetY = 0;
var isDragging = false;
// 鼠标事件1 -- 在标题栏上按下
// 计算鼠标相对拖拽元素的的左上角的坐标， 并且标记元素为可拖动
g('dialogTitle').addEventListener('mousedown', function(e) {
var e = e || window.event;
// 用鼠标按下时的坐标减去 dialog 的左上角坐标
mouseOffsetX = e.pageX - g('dialog').offsetLeft;
mouseOffsetY = e.pageY - g('dialog').offsetTop;
isDragging = true;
});
// 鼠标事件2 -- 鼠标移动
document.onmousemove = function(e) {
var e = e || window.event;
// 鼠标当前位置
var mouseX = e.pageX;
var mouseY = e.pageY;
// 鼠标从单击时至当前时刻移动的距离
var moveX = 0;
var moveY = 0;
if (isDragging === true) {
moveX = mouseX - mouseOffsetX;
moveY = mouseY - mouseOffsetY;
// 范围限定
// moveX > 0 且 moveX < (页面最大宽度 - 浮层宽度)
// moveY > 0 且 moveY < (页面最大宽度 - 浮层高度)
var pageWidth = document.documentElement.clientWidth;
var pageHeight = document.documentElement.clientHeight;
// 登录浮层的宽、高
var dialogWidth = g('dialog').offsetWidth;
var dialogHeight = g('dialog').offsetHeight;
var maxX = pageWidth - dialogWidth;
var maxY = pageHeight - dialogHeight;
moveX = Math.min(maxX, Math.max(0, moveX));
moveY = Math.min(maxY, Math.max(0, moveY));
g('dialog').style.left = moveX + 'px';
g('dialog').style.top = moveY + 'px';
}
};
// 鼠标事件3 -- 鼠标松开
document.onmouseup = function() {
isDragging = false;
};
// 展现登录浮层
function showDialog() {
g('dialog').style.display = 'block';
g('mask').style.display = 'block';
autoCenter(g('dialog'));
fillToBody(g('mask'));
}
// 隐藏登录浮层
function hideDialog() {
g('dialog').style.display = 'none';
g('mask').style.display = 'none';
}
window.onresize = function() {
autoCenter(g('dialog'));
fillToBody(g('mask'));
};
showDialog();
autoCenter(g('dialog'));
</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！