文档对象模型（Document Object Model，DOM）是一种用于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。我们最为关心的是，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
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
操作
内容
innerText 文本 outerText innerHTML HTML内容 innerHTML value 值
属性
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);
*/
<!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
标签操作
创建标签
// 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>"
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 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
*/
1 <!DOCTYPE html> 2 <html> 3 <head lang="en"> 4 <meta charset="UTF-8"> 5 <title></title> 6 </head> 7 <body style="margin: 0;"> 8 <div style="height: 900px;"> 9 10 </div> 11 <div style="padding: 10px;"> 12 <div id="i1" style="height:190px;padding: 2px;border: 1px solid red;margin: 8px;"> 13 <p>asdf</p> 14 <p>asdf</p> 15 <p>asdf</p> 16 <p>asdf</p> 17 <p>asdf</p> 18 </div> 19 </div> 20 21 <script> 22 var i1 = document.getElementById('i1'); 23 24 console.log(i1.clientHeight); // 可见区域：height + padding 25 console.log(i1.clientTop); // border高度 26 console.log('====='); 27 console.log(i1.offsetHeight); // 可见区域：height + padding + border 28 console.log(i1.offsetTop); // 上级定位标签的高度 29 console.log('====='); 30 console.log(i1.scrollHeight); //全文高：height + padding 31 console.log(i1.scrollTop); // 滚动高度 32 console.log('====='); 33 34 </script> 35 </body> 36 </html>
<!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{ width: 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; width: 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; width: 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; width: 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>
1 <!DOCTYPE html> 2 <html> 3 <head lang="en"> 4 <meta charset="UTF-8"> 5 <title></title> 6 </head> 7 <style> 8 9 body{ 10 margin: 0px; 11 } 12 img { 13 border: 0; 14 } 15 ul{ 16 padding: 0; 17 margin: 0; 18 list-style: none; 19 } 20 h1{ 21 padding: 0; 22 margin: 0; 23 } 24 .clearfix:after { 25 content: "."; 26 display: block; 27 height: 0; 28 clear: both; 29 visibility: hidden; 30 } 31 32 .wrap{ 33 width: 980px; 34 margin: 0 auto; 35 } 36 37 .pg-header{ 38 background-color: #303a40; 39 -webkit-box-shadow: 0 2px 5px rgba(0,0,0,.2); 40 -moz-box-shadow: 0 2px 5px rgba(0,0,0,.2); 41 box-shadow: 0 2px 5px rgba(0,0,0,.2); 42 } 43 .pg-header .logo{ 44 float: left; 45 padding:5px 10px 5px 0px; 46 } 47 .pg-header .logo img{ 48 vertical-align: middle; 49 width: 110px; 50 height: 40px; 51 52 } 53 .pg-header .nav{ 54 line-height: 50px; 55 } 56 .pg-header .nav ul li{ 57 float: left; 58 } 59 .pg-header .nav ul li a{ 60 display: block; 61 color: #ccc; 62 padding: 0 20px; 63 text-decoration: none; 64 font-size: 14px; 65 } 66 .pg-header .nav ul li a:hover{ 67 color: #fff; 68 background-color: #425a66; 69 } 70 .pg-body{ 71 72 } 73 .pg-body .catalog{ 74 position: absolute; 75 top:60px; 76 width: 200px; 77 background-color: #fafafa; 78 bottom: 0px; 79 } 80 .pg-body .catalog.fixed{ 81 position: fixed; 82 top:10px; 83 } 84 85 .pg-body .catalog .catalog-item.active{ 86 color: #fff; 87 background-color: #425a66; 88 } 89 90 .pg-body .content{ 91 position: absolute; 92 top:60px; 93 width: 700px; 94 margin-left: 210px; 95 background-color: #fafafa; 96 overflow: auto; 97 } 98 .pg-body .content .section{ 99 height: 500px; 100 border: 1px solid red; 101 } 102 </style> 103 <body onscroll="ScrollEvent();"> 104 <div class="pg-header"> 105 <div class="wrap clearfix"> 106 <div class="logo"> 107 <a href="#"> 108 <img src="http://core.pc.lietou-static.com/revs/images/common/logo_7012c4a4.pn"> 109 </a> 110 </div> 111 <div class="nav"> 112 <ul> 113 <li> 114 <a href="#">首页</a> 115 </li> 116 <li> 117 <a href="#">功能一</a> 118 </li> 119 <li> 120 <a href="#">功能二</a> 121 </li> 122 </ul> 123 </div> 124 125 </div> 126 </div> 127 <div class="pg-body"> 128 <div class="wrap"> 129 <div class="catalog" id="catalog"> 130 <div class="catalog-item" auto-to="function1"><a>第1张</a></div> 131 <div class="catalog-item" auto-to="function2"><a>第2张</a></div> 132 <div class="catalog-item" auto-to="function3"><a>第3张</a></div> 133 </div> 134 <div class="content" id="content"> 135 <div menu="function1" class="section"> 136 <h1>第一章</h1> 137 </div> 138 <div menu="function2" class="section"> 139 <h1>第二章</h1> 140 </div> 141 <div menu="function3" class="section"> 142 <h1>第三章</h1> 143 </div> 144 </div> 145 </div> 146 147 </div> 148 <script> 149 function ScrollEvent(){ 150 var bodyScrollTop = document.body.scrollTop; 151 if(bodyScrollTop>50){ 152 document.getElementsByClassName('catalog')[0].classList.add('fixed'); 153 }else{ 154 document.getElementsByClassName('catalog')[0].classList.remove('fixed'); 155 } 156 157 var content = document.getElementById('content'); 158 var sections = content.children; 159 for(var i=0;i<sections.length;i++){ 160 var current_section = sections[i]; 161 162 // 当前标签距离顶部绝对高度 163 var scOffTop = current_section.offsetTop + 60; 164 165 // 当前标签距离顶部，相对高度 166 var offTop = scOffTop - bodyScrollTop; 167 168 // 当前标签高度 169 var height = current_section.scrollHeight; 170 171 if(offTop<0 && -offTop < height){ 172 // 当前标签添加active 173 // 其他移除 active 174 var menus = document.getElementById('catalog').children; 175 var current_menu = menus[i]; 176 current_menu.classList.add('active'); 177 for(var j=0;j<menus.length;j++){ 178 if(menus[j] == current_menu){ 179 180 }else{ 181 menus[j].classList.remove('active'); 182 } 183 } 184 break; 185 } 186 187 } 188 189 190 } 191 </script> 192 </body> 193 </html>
<!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{ width: 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; width: 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; width: 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; width: 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>
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
事件
对于事件需要注意的要点：
- this
- event
- 事件链以及跳出
this标签当前正在操作的标签，event封装了当前事件的内容。
实例：
<!DOCTYPE html> <html> <head> <meta charset='utf-8' /> <title></title> <style> .gray{ color:gray; } .black{ color:black; } </style> <script type="text/javascript"> function Enter(){ var id= document.getElementById("tip") id.className = 'black'; if(id.value=='请输入关键字'||id.value.trim()==''){ id.value = '' } } function Leave(){ var id= document.getElementById("tip") var val = id.value; if(val.length==0||id.value.trim()==''){ id.value = '请输入关键字' id.className = 'gray'; }else{ id.className = 'black'; } } </script> </head> <body> <input type='text' class='gray' id='tip' value='请输入关键字' onfocus='Enter();' onblur='Leave();'/> </body> </html>
<!DOCTYPE html> <html> <head> <meta charset='utf-8' > <title>欢迎宝强同志莅临指导 </title> <script type='text/javascript'> function Go(){ var content = document.title; var firstChar = content.charAt(0) var sub = content.substring(1,content.length) document.title = sub + firstChar; } setInterval('Go()',1000); </script> </head> <body> </body> </html>