Document Object Model,一种用于HTML和XML文档的编程接口。它给文档提供了一种结构化的表示方法，可以改变文档的内容和呈现方式,DOM把网页和脚本以及其他的编程语言联系了起来。DOM属于浏览器，而不是JavaScript语言规范里的规定的核心内容。
查找元素
直接查找
document.getElementById 根据ID获取一个标签
document.getElementsByName 根据name属性获取标签集合
document.getElementsByClassName 根据class属性获取标签集合
document.getElementsByTagName 根据标签名获取标签集合
从上面可以看出,除了根据ID获取标签是一个数量外,其他的都是一个集合或者数组,可以是1个也可以是多个.
间接查找
parentNode // 父节点
childNodes // 所有子节点
firstChild // 第一个子节点
lastChild // 最后一个子节点
nextSibling // 下一个兄弟节点
previousSibling // 上一个兄弟节点
parentElement // 父节点标签元素
children // 所有子标签
firstElementChild // 第一个子标签元素
lastElementChild // 最后一个子标签元素
nextElementtSibling // 下一个兄弟标签元素
previousElementSibling // 上一个兄弟标签元素
例子:输入框默认文字
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title></title>
</head>
<body>
<input id="i1" type="text" value="请输入关键字" onfocus="Focus();" onblur="Blur();" />
<input id="i2" type="text"/>
<script type="text/javascript">
function Focus(){
//console.log('Focus');
//获取标签，清空
var tag = document.getElementById('i1');
if(tag.value == "请输入关键字"){
tag.value = "";
}
}
function Blur(){
//console.log('blur');
var tag = document.getElementById('i1');
var val = tag.value;
if(val.trim().length == 0){
tag.value = "请输入关键字";
}
}
</script>
</body>
</html>
操作
内容操作
innerText 文本
outerText
innerHTML HTML内容
innerHTML
value 值
属性操作
attributes // 获取所有标签属性
setAttribute(key,value) // 设置标签属性
getAttribute(key) // 获取指定标签属性
/*
var atr = document.createAttribute("class");
atr.nodeValue="democlass";
document.getElementById('n1').setAttributeNode(atr);
*/
<input id='i1' name='n1' alex='sb' type='text' style="color:red;font-size:40px;"/>
setAttribute
getAttribute
removeAttribute
===>
tabObj.checked = true
===>jQuery: 操作数据，prop(checked,true)
例子:列表全选取消反选
注意全选反选时,尽量使用obj.checked=true ,false,否则如果文件里还有setAttribute的话,会出现错误.
<!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8">
<title></title>
</head>
<body>
<input type="button" value="全选" onclick="CheckAll();"/>
<input type="button" value="取消" onclick="CancelAll();"/>
<input type="button" value="反选" onclick="ReverseCheck();"/>
<table border="1" >
<thead>
</thead>
<tbody id="tb">
<tr>
<td><input type="checkbox" /></td>
<td>111</td>
<td>222</td>
</tr>
<tr>
<td><input type="checkbox" /></td>
<td>111</td>
<td>222</td>
</tr>
<tr>
<td><input type="checkbox" /></td>
<td>111</td>
<td>222</td>
</tr>
<tr>
<td><input type="checkbox" /></td>
<td>111</td>
<td>222</td>
</tr>
</tbody>
</table>
<script>
function CheckAll(ths){
var tb = document.getElementById('tb');
var trs = tb.childNodes;
for(var i =0; i<trs.length; i++){
var current_tr = trs[i];
if(current_tr.nodeType==1){
var inp = current_tr.firstElementChild.getElementsByTagName('input')[0];
inp.checked = true;
}
}
}
function CancelAll(ths){
var tb = document.getElementById('tb');
var trs = tb.childNodes;
for(var i =0; i<trs.length; i++){
var current_tr = trs[i];
if(current_tr.nodeType==1){
var inp = current_tr.firstElementChild.getElementsByTagName('input')[0];
inp.checked = false;
}
}
}
function ReverseCheck(ths){
var tb = document.getElementById('tb');
var trs = tb.childNodes;
for(var i =0; i<trs.length; i++){
var current_tr = trs[i];
if(current_tr.nodeType==1){
var inp = current_tr.firstElementChild.getElementsByTagName('input')[0];
if(inp.checked){
inp.checked = false;
}else{
inp.checked = true;
}
}
}
}
</script>
</body>
</html>
class操作
className // 获取所有类名
classList.remove(cls) // 删除指定类
classList.add(cls) // 添加类
例子:遮罩隐藏登录
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title></title>
<style>
.hide{
display: none !important;
}
.shade{
position: fixed;
top:0;
bottom: 0;
left: 0;
right: 0;
/*background-color: black;*/
/*opacity: 0.6;*/
background-color: rgba(0,0,0,.6);
z-index: 1000;
}
.modal{
height: 200px;
400px;
background-color: white;
position: fixed;
top: 50%;
left: 50%;
margin-left: -200px;
margin-top: -100px;
z-index: 1001;
}
</style>
</head>
<body>
<div style="height: 2000px;background-color: #dddddd;">
<input type="button" value="点我" onclick="ShowModal();" />
</div>
<div id="shade" class="shade hide"></div>
<div id="modal" class="modal hide">
<a href="javascript:void(0);" onclick="HideModal();">取消</a>
</div>
<script>
function ShowModal(){
var t1 = document.getElementById('shade');
var t2 = document.getElementById('modal');
t1.classList.remove('hide');
t2.classList.remove('hide');
}
function HideModal(){
var t1 = document.getElementById('shade');
var t2 = document.getElementById('modal');
t1.classList.add('hide');
t2.classList.add('hide');
}
window.onkeydown = function(event){
//console.log(event);
if(event.keyCode == 27){
HideModal();
}
}
</script>
</body>
</html>
标签操作
创建标签
创建标签有两种方式:
- 对象方式
- 字符串方式
- 如果两种方式都出现的话,对象方式优先
// 方式一
var tag = document.createElement('a')
tag.innerText = "wupeiqi"
tag.className = "c1"
tag.href = "http://www.cnblogs.com/wupeiqi"
// 方式二
var tag = "<a class='c1' href='http://www.cnblogs.com/wupeiqi'>wupeiqi</a>"
//将标签添加到HTML中
//字符串形式的标签：
p1.insertAdjacentHTML('beforeEnd',tag);
//对象形式的标签：
p1.insertAdjacentElement('afterBegin',document.createElement('p'))
xxx.insertBefore(tag,xxx[1])
例子:点赞漂+1
其中用到了定时器:setInterval
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title></title>
<style>
.item{
padding: 50px;
position: relative;
}
</style>
</head>
<body>
<div class="item">
<a onclick="Favor(this);">赞1</a>
</div>
<div class="item">
<a onclick="Favor(this);">赞2</a>
</div>
<div class="item">
<a onclick="Favor(this);">赞3</a>
</div>
<div class="item">
<a onclick="Favor(this);">赞4</a>
</div>
<script>
function Favor(ths){
// ths => this => 当前触发事件的标签
var top = 49;
var left = 71;
var op = 1;
var fontSize = 18;
var tag = document.createElement('span');
tag.innerText = '+1';
tag.style.position = 'absolute';
tag.style.top = top + "px";
tag.style.left = left + "px";
tag.style.opacity = op;
tag.style.fontSize = fontSize + 'px';
ths.parentElement.appendChild(tag);
var interval = setInterval(function(){
top -= 10;
left += 10;
fontSize += 5;
op -= 0.1;
tag.style.top = top + "px";
tag.style.left = left + "px";
tag.style.opacity = op;
tag.style.fontSize = fontSize + 'px';
if(op <= 0.2){
clearInterval(interval);
ths.parentElement.removeChild(tag);
}
}, 50);
}
</script>
</body>
</html>
例子:模拟邮件删除提示
其中用到了单词定时器:setTimeout
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title></title>
</head>
<body>
<div id="status" style="color: red;">
</div>
<input type="submit" onclick="DeleteStatus();" value="删除" />
<script>
function DeleteStatus(){
var s = document.getElementById('status');
s.innerText = '删除成功';
setTimeout(function(){
s.innerText = "";
},5000);
}
</script>
</body>
</html>
操作标签
// 方式一
var obj = "<input type='text' />";
xxx.insertAdjacentHTML("beforeEnd",obj);
xxx.insertAdjacentElement('afterBegin',document.createElement('p'))
//注意：第一个参数只能是'beforeBegin'、 'afterBegin'、 'beforeEnd'、 'afterEnd'
// 方式二
var tag = document.createElement('a')
xxx.appendChild(tag)
xxx.insertBefore(tag,xxx[1])
样式操作
var obj = document.getElementById('i1')
obj.style.fontSize = "32px";
obj.style.backgroundColor = "red";
<input type='text' style="color:red;font-size:40px;"/>
tag = .....
tag.style.color = 'red';
tag.style.fontSize = '40px';
例子:输入框关键字灰色
<input onfocus="Focus(this);" onblur="Blur(this);" id="search" value="请输入关键字" style="color: gray;" />
<script>
function Focus(ths){
ths.style.color = "black";
if(ths.value == '请输入关键字' || ths.value.trim() == ""){
ths.value = "";
}
}
function Blur(ths){
if(ths.value.trim() == ""){
ths.value = '请输入关键字';
ths.style.color = 'gray';
}else{
ths.style.color = "black";
}
}
</script>
位置操作
总文档高度
document.documentElement.offsetHeight
当前文档占屏幕高度
document.documentElement.clientHeight
自身高度
tag.offsetHeight
距离上级定位高度
tag.offsetTop
父定位标签
tag.offsetParent
滚动高度
tag.scrollTop
/*
clientHeight -> 可见区域：height + padding
clientTop -> border高度
offsetHeight -> 可见区域：height + padding + border
offsetTop -> 上级定位标签的高度
scrollHeight -> 全文高：height + padding
scrollTop -> 滚动高度
特别的：
document.documentElement代指文档根节点
*/
测试代码:
<!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8">
<title></title>
</head>
<body style="margin: 0;">
<div style="height: 900px;">
</div>
<div style="padding: 10px;">
<div id="i1" style="height:190px;padding: 2px;border: 1px solid red;margin: 8px;">
<p>asdf</p>
<p>asdf</p>
<p>asdf</p>
<p>asdf</p>
<p>asdf</p>
</div>
</div>
<script>
var i1 = document.getElementById('i1');
console.log(i1.clientHeight); // 可见区域：height + padding
console.log(i1.clientTop); // border高度
console.log('=====');
console.log(i1.offsetHeight); // 可见区域：height + padding + border
console.log(i1.offsetTop); // 上级定位标签的高度
console.log('=====');
console.log(i1.scrollHeight); //全文高：height + padding
console.log(i1.scrollTop); // 滚动高度
console.log('=====');
</script>
</body>
</html>
例子:滚动固定(这个比较屌)
<!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8">
<title></title>
</head>
<style>
body{
margin: 0px;
}
img {
border: 0;
}
ul{
padding: 0;
margin: 0;
list-style: none;
}
.clearfix:after {
content: ".";
display: block;
height: 0;
clear: both;
visibility: hidden;
}
.wrap{
980px;
margin: 0 auto;
}
.pg-header{
background-color: #303a40;
-webkit-box-shadow: 0 2px 5px rgba(0,0,0,.2);
-moz-box-shadow: 0 2px 5px rgba(0,0,0,.2);
box-shadow: 0 2px 5px rgba(0,0,0,.2);
}
.pg-header .logo{
float: left;
padding:5px 10px 5px 0px;
}
.pg-header .logo img{
vertical-align: middle;
110px;
height: 40px;
}
.pg-header .nav{
line-height: 50px;
}
.pg-header .nav ul li{
float: left;
}
.pg-header .nav ul li a{
display: block;
color: #ccc;
padding: 0 20px;
text-decoration: none;
font-size: 14px;
}
.pg-header .nav ul li a:hover{
color: #fff;
background-color: #425a66;
}
.pg-body{
}
.pg-body .catalog{
position: absolute;
top:60px;
200px;
background-color: #fafafa;
bottom: 0px;
}
.pg-body .catalog.fixed{
position: fixed;
top:10px;
}
.pg-body .catalog .catalog-item.active{
color: #fff;
background-color: #425a66;
}
.pg-body .content{
position: absolute;
top:60px;
700px;
margin-left: 210px;
background-color: #fafafa;
overflow: auto;
}
.pg-body .content .section{
height: 500px;
}
</style>
<body onscroll="ScrollEvent();">
<div class="pg-header">
<div class="wrap clearfix">
<div class="logo">
<a href="#">
<img src="http://core.pc.lietou-static.com/revs/images/common/logo_7012c4a4.pn">
</a>
</div>
<div class="nav">
<ul>
<li>
<a href="#">首页</a>
</li>
<li>
<a href="#">功能一</a>
</li>
<li>
<a href="#">功能二</a>
</li>
</ul>
</div>
</div>
</div>
<div class="pg-body">
<div class="wrap">
<div class="catalog">
<div class="catalog-item" auto-to="function1"><a>第1张</a></div>
<div class="catalog-item" auto-to="function2"><a>第2张</a></div>
<div class="catalog-item" auto-to="function3"><a>第3张</a></div>
</div>
<div class="content">
<div menu="function1" class="section">
<h1>第一章</h1>
</div>
<div menu="function2" class="section">
<h1>第二章</h1>
</div>
<div menu="function3" class="section">
<h1>第三章</h1>
</div>
</div>
</div>
</div>
<script>
function ScrollEvent(){
var bodyScrollTop = document.body.scrollTop;
if(bodyScrollTop>50){
document.getElementsByClassName('catalog')[0].classList.add('fixed');
}else{
document.getElementsByClassName('catalog')[0].classList.remove('fixed');
}
}
</script>
</body>
</html>
例子:滚动高度
<!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8">
<title></title>
</head>
<style>
body{
margin: 0px;
}
img {
border: 0;
}
ul{
padding: 0;
margin: 0;
list-style: none;
}
h1{
padding: 0;
margin: 0;
}
.clearfix:after {
content: ".";
display: block;
height: 0;
clear: both;
visibility: hidden;
}
.wrap{
980px;
margin: 0 auto;
}
.pg-header{
background-color: #303a40;
-webkit-box-shadow: 0 2px 5px rgba(0,0,0,.2);
-moz-box-shadow: 0 2px 5px rgba(0,0,0,.2);
box-shadow: 0 2px 5px rgba(0,0,0,.2);
}
.pg-header .logo{
float: left;
padding:5px 10px 5px 0px;
}
.pg-header .logo img{
vertical-align: middle;
110px;
height: 40px;
}
.pg-header .nav{
line-height: 50px;
}
.pg-header .nav ul li{
float: left;
}
.pg-header .nav ul li a{
display: block;
color: #ccc;
padding: 0 20px;
text-decoration: none;
font-size: 14px;
}
.pg-header .nav ul li a:hover{
color: #fff;
background-color: #425a66;
}
.pg-body{
}
.pg-body .catalog{
position: absolute;
top:60px;
200px;
background-color: #fafafa;
bottom: 0px;
}
.pg-body .catalog.fixed{
position: fixed;
top:10px;
}
.pg-body .catalog .catalog-item.active{
color: #fff;
background-color: #425a66;
}
.pg-body .content{
position: absolute;
top:60px;
700px;
margin-left: 210px;
background-color: #fafafa;
overflow: auto;
}
.pg-body .content .section{
height: 500px;
border: 1px solid red;
}
</style>
<body onscroll="ScrollEvent();">
<div class="pg-header">
<div class="wrap clearfix">
<div class="logo">
<a href="#">
<img src="http://core.pc.lietou-static.com/revs/images/common/logo_7012c4a4.pn">
</a>
</div>
<div class="nav">
<ul>
<li>
<a href="#">首页</a>
</li>
<li>
<a href="#">功能一</a>
</li>
<li>
<a href="#">功能二</a>
</li>
</ul>
</div>
</div>
</div>
<div class="pg-body">
<div class="wrap">
<div class="catalog" id="catalog">
<div class="catalog-item" auto-to="function1"><a>第1张</a></div>
<div class="catalog-item" auto-to="function2"><a>第2张</a></div>
<div class="catalog-item" auto-to="function3"><a>第3张</a></div>
</div>
<div class="content" id="content">
<div menu="function1" class="section">
<h1>第一章</h1>
</div>
<div menu="function2" class="section">
<h1>第二章</h1>
</div>
<div menu="function3" class="section" style="height: 200px;">
<h1>第三章</h1>
</div>
</div>
</div>
</div>
<script>
function ScrollEvent(){
var bodyScrollTop = document.body.scrollTop;
if(bodyScrollTop>50){
document.getElementsByClassName('catalog')[0].classList.add('fixed');
}else{
document.getElementsByClassName('catalog')[0].classList.remove('fixed');
}
var content = document.getElementById('content');
var sections = content.children;
for(var i=0;i<sections.length;i++){
var current_section = sections[i];
// 当前标签距离顶部绝对高度
var scOffTop = current_section.offsetTop + 60;
// 当前标签距离顶部，相对高度
var offTop = scOffTop - bodyScrollTop;
// 当前标签高度
var height = current_section.scrollHeight;
if(offTop<0 && -offTop < height){
// 当前标签添加active
// 其他移除 active
// 如果已经到底部，现实第三个菜单
// 文档高度 ＝ 滚动高度 + 视口高度
var a = document.getElementsByClassName('content')[0].offsetHeight + 60;
var b = bodyScrollTop + document.documentElement.clientHeight;
console.log(a+60,b);
if(a == b){
var menus = document.getElementById('catalog').children;
var current_menu = document.getElementById('catalog').lastElementChild;
current_menu.classList.add('active');
for(var j=0;j<menus.length;j++){
if(menus[j] == current_menu){
}else{
menus[j].classList.remove('active');
}
}
}else{
var menus = document.getElementById('catalog').children;
var current_menu = menus[i];
current_menu.classList.add('active');
for(var j=0;j<menus.length;j++){
if(menus[j] == current_menu){
}else{
menus[j].classList.remove('active');
}
}
}
break;
}
}
}
</script>
</body>
</html>
例子:返回顶层,并且最顶端不显示
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>返回顶部</title>
<style>
.hide{
display: none;
}
.back{
position: fixed;
bottom: 20px;
right: 20px;
cursor: pointer;
color: red;
}
</style>
</head>
<body onscroll="BodyScroll();">
<div style="height: 2000px;background-color: #cccccc"></div>
<div id="back" class="back" onclick="BackTop();">返回顶部</div>
<script>
function BackTop(){
document.body.scrollTop=0;
}
function BodyScroll(){
var s = document.body.scrollTop;
var t = document.getElementById('back');
if(s>=100){
t.classList.remove('hide');
}else{
t.classList.add('hide');
}
}
</script>
</body>
</html>
提交表单
document.geElementById('form').submit()
其他操作
console.log 输出框
alert 弹出框
confirm 确认框
// URL和刷新
location.href 获取URL
location.href = "url" 重定向
location.reload() 重新加载
// 定时器
setInterval 多次定时器
clearInterval 清除多次定时器
setTimeout 单次定时器
clearTimeout 清除单次定时器
例子:确认
var ret = confirm('是否删除？');
console.log(ret);
事件
事件重要补充:
- this,当前触发事件的标签
- 全局事件绑定 window.onKeyDown = function(){}
- event，包含事件相关内容
- 默认事件:自定义优先：
a,form等;默认优先：checkbox
事件优先例子:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title></title>
</head>
<body>
<a href="http://www.baidu.com" onclick="ClickB();">百度</a>
<form>
<input type="text" />
<input type="submit" onclick="ClickB();" />
</form>
<input type="checkbox" onclick="ClickB();" />
<script>
function ClickB(){
alert(123);
}
</script>
</body>
</html>
输入框例子:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title></title>
</head>
<body>
<form action="http://www.baidu.com">
<input type="text" id="username" />
<input type="submit" value="提交" onclick="return SubmitForm();" />
</form>
<script>
function SubmitForm(){
var user = document.getElementById('username');
if(user.value.length > 0 ){
// 可以提交
return true;
}else{
// 不可提交，提示错误
alert('用户名输入不能为空');
return false;
}
}
</script>
</body>
</html>