今天小编给大家分享一下js怎么实现响应按钮点击弹出可拖拽的非模态对话框的相关知识点，内容详细，逻辑清晰，相信大部分人都还太了解这方面的知识，所以分享这篇文章给大家参考一下，希望大家阅读完这篇文章后有所收获，下面我们一起来了解一下吧。
1.css部分：
.dialog {
display: none;
position: absolute;
left: 50%;
top: 50%;
transform: translate(-50%, -50%);
background-color: #fff;
border-radius: 5px;
box-shadow: 0 10px 20px rgba(0, 0, 0, .3);
z-index: 9999;
}
.dialog-header {
background-color: #f6f7f8;
padding: 10px;
border-top-left-radius: 5px;
border-top-right-radius: 5px;
cursor: move;
}
.dlgtitle {
font-weight: bold;
font-size: 16px;
}
.close-btn {
float: right;
cursor: pointer;
}
.dialog-content {
padding: 20px;
}2.html部分：
<button id="openBtn">打开对话框</button> <div id="dialog" class="dialog"> <div class="dialog-header"> <span class="dlgtitle">对话框标题</span> <span class="close-btn">×</span> </div> <div class="dialog-content"> <p>这里是对话框内容</p> </div> </div>
3.JavaScript部分：
var dialog = document.getElementById('dialog');
var openBtn = document.getElementById('openBtn');
var closeBtn = document.querySelector('.close-btn');
var isDragging = false;
var mouseX, mouseY, dialogLeft, dialogTop;
// 鼠标按下时记录鼠标位置以及对话框位置
dialogHeaderMouseDown = function(e) {
isDragging = true;
mouseX = e.clientX;
mouseY = e.clientY;
dialogLeft = dialog.offsetLeft;
dialogTop = dialog.offsetTop;
}
// 鼠标移动时移动对话框
// document.onmousemove = function(e) {
dialogHeaderMouseMove = function(e) {
if (isDragging) {
var moveX = e.clientX - mouseX;
var moveY = e.clientY - mouseY;
dialog.style.left = dialogLeft + moveX + 'px';
dialog.style.top = dialogTop + moveY + 'px';
}
}
// 鼠标松开时停止拖动
// document.onmouseup = function() {
dialogHeaderMouseup = function() {
isDragging = false;
}
// 点击打开按钮显示对话框
openBtn.onclick = function() {
dialog.style.display = 'block';
}
// 点击关闭按钮或对话框外部关闭对话框
closeBtn.onclick = function() {
dialog.style.display = 'none';
}
dialog.onclick = function(e) {
if (e.target == dialog) {
dialog.style.display = 'none';
}
}
// 鼠标按下对话框头部，开始拖动对话框
var header = document.querySelector('.dialog-header');
header.addEventListener('mousedown', dialogHeaderMouseDown);
header.addEventListener('mousemove', dialogHeaderMouseMove);
header.addEventListener('mouseup', dialogHeaderMouseup);可以使用本站在线工具：http://tools.jb51.net/code/WebCodeRun 测试上述代码运行效果。
附：完整示例代码：
<!DOCTYPE html>
<html lang="zh_CN">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>可拖拽非模态对话框</title>
<style>
.dialog {
display: none;
position: absolute;
left: 50%;
top: 50%;
transform: translate(-50%, -50%);
background-color: #fff;
border-radius: 5px;
box-shadow: 0 10px 20px rgba(0, 0, 0, .3);
z-index: 9999;
}
.dialog-header {
background-color: #f6f7f8;
padding: 10px;
border-top-left-radius: 5px;
border-top-right-radius: 5px;
cursor: move;
}
.dlgtitle {
font-weight: bold;
font-size: 16px;
}
.close-btn {
float: right;
cursor: pointer;
}
.dialog-content {
padding: 20px;
}
</style>
</head>
<body>
<button id="openBtn">打开对话框</button>
<div id="dialog" class="dialog">
<div class="dialog-header">
<span class="dlgtitle">对话框标题</span>
<span class="close-btn">×</span>
</div>
<div class="dialog-content">
<p>这里是对话框内容</p>
</div>
</div>
<script>
var dialog = document.getElementById('dialog');
var openBtn = document.getElementById('openBtn');
var closeBtn = document.querySelector('.close-btn');
var isDragging = false;
var mouseX, mouseY, dialogLeft, dialogTop;
// 鼠标按下时记录鼠标位置以及对话框位置
dialogHeaderMouseDown = function(e) {
isDragging = true;
mouseX = e.clientX;
mouseY = e.clientY;
dialogLeft = dialog.offsetLeft;
dialogTop = dialog.offsetTop;
}
// 鼠标移动时移动对话框
// document.onmousemove = function(e) {
dialogHeaderMouseMove = function(e) {
if (isDragging) {
var moveX = e.clientX - mouseX;
var moveY = e.clientY - mouseY;
dialog.style.left = dialogLeft + moveX + 'px';
dialog.style.top = dialogTop + moveY + 'px';
}
}
// 鼠标松开时停止拖动
// document.onmouseup = function() {
dialogHeaderMouseup = function() {
isDragging = false;
}
// 点击打开按钮显示对话框
openBtn.onclick = function() {
dialog.style.display = 'block';
}
// 点击关闭按钮或对话框外部关闭对话框
closeBtn.onclick = function() {
dialog.style.display = 'none';
}
dialog.onclick = function(e) {
if (e.target == dialog) {
dialog.style.display = 'none';
}
}
// 鼠标按下对话框头部，开始拖动对话框
var header = document.querySelector('.dialog-header');
header.addEventListener('mousedown', dialogHeaderMouseDown);
header.addEventListener('mousemove', dialogHeaderMouseMove);
header.addEventListener('mouseup', dialogHeaderMouseup);
</script>
</body>
</html>