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DOM

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。

一、查找元素

1、直接查找

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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

2、间接查找

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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

二、操作

1、内容

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innerText   文本
outerText
innerHTML   HTML内容
innerHTML  
value       值

2、属性

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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="http://www.mamicode.com/democlass";
document.getElementById(‘n1‘).setAttributeNode(atr);
*/
技术分享
<!DOCTYPE html><html><head lang="en">    <meta charset="UTF-8">    <title></title></head><body>    <input type="button" value=http://www.mamicode.com/"全选"  onclick="CheckAll();"/>    <input type="button" value=http://www.mamicode.com/"取消" onclick="CancelAll();"/>    <input type="button" value=http://www.mamicode.com/"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>

3、class操作

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className                // 获取所有类名
classList.remove(cls)    // 删除指定类
classList.add(cls)       // 添加类

4、标签操作

a.创建标签

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// 方式一
var tag = document.createElement(‘a‘)
tag.innerText = "wupeiqi"
tag.className = "c1"
tag.href = http://www.mamicode.com/"http://www.cnblogs.com/wupeiqi"
 
// 方式二
var tag = "<a class=‘c1‘ href=http://www.mamicode.com/‘http://www.cnblogs.com/wupeiqi‘>wupeiqi"

b.操作标签

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// 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])

5、样式操作

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var obj = document.getElementById(‘i1‘)
 
obj.style.fontSize = "32px";
obj.style.backgroundColor = "red";
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    <input onfocus="Focus(this);" onblur="Blur(this);" id="search" value=http://www.mamicode.com/"请输入关键字" style="color: gray;" />    <script>        function Focus(ths){            ths.style.color = "black";            if(ths.value =http://www.mamicode.com/= 请输入关键字‘ || ths.value.trim() == ""){                ths.value = http://www.mamicode.com/"";            }        }        function Blur(ths){            if(ths.value.trim() == ""){                ths.value = http://www.mamicode.com/请输入关键字;                ths.style.color = gray;            }else{                ths.style.color = "black";            }        }    </script>

6、位置操作

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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
*/
技术分享
<!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>
技术分享
<!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=http://www.mamicode.com/"#">                <img src=http://www.mamicode.com/"http://core.pc.lietou-static.com/revs/images/common/logo_7012c4a4.pn">            </a>        </div>        <div class="nav">            <ul>                <li>                    <a  href=http://www.mamicode.com/"#">首页</a>                </li>                <li>                    <a  href=http://www.mamicode.com/"#">功能一</a>                </li>                <li>                    <a  href=http://www.mamicode.com/"#">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>
技术分享
<!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=http://www.mamicode.com/"#">                <img src=http://www.mamicode.com/"http://core.pc.lietou-static.com/revs/images/common/logo_7012c4a4.pn">            </a>        </div>        <div class="nav">            <ul>                <li>                    <a  href=http://www.mamicode.com/"#">首页</a>                </li>                <li>                    <a  href=http://www.mamicode.com/"#">功能一</a>                </li>                <li>                    <a  href=http://www.mamicode.com/"#">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">                <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                    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>
技术分享
<!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=http://www.mamicode.com/"#">                <img src=http://www.mamicode.com/"http://core.pc.lietou-static.com/revs/images/common/logo_7012c4a4.pn">            </a>        </div>        <div class="nav">            <ul>                <li>                    <a  href=http://www.mamicode.com/"#">首页</a>                </li>                <li>                    <a  href=http://www.mamicode.com/"#">功能一</a>                </li>                <li>                    <a  href=http://www.mamicode.com/"#">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>

7、提交表单

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document.geElementById(‘form‘).submit()

8、其他操作

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console.log                 输出框
alert                       弹出框
confirm                     确认框
  
// URL和刷新
location.href               获取URL
location.href = http://www.mamicode.com/"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

三、事件

技术分享

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:

技术分享
<!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=http://www.mamicode.com/=‘请输入关键字‘||id.value.trim()==‘‘){                    id.value = http://www.mamicode.com/‘‘               }            }            function Leave(){                var id= document.getElementById("tip")                var val = id.value;                if(val.length==0||id.value.trim()==‘‘){                    id.value = http://www.mamicode.com/‘请输入关键字‘                    id.className = ‘gray‘;                }else{                    id.className = ‘black‘;                }            }        </script>    </head>    <body>        <input type=‘text‘ class=‘gray‘ id=‘tip‘ value=http://www.mamicode.com/‘请输入关键字‘ onfocus=‘Enter();‘  onblur=‘Leave();‘/>>
技术分享
<!DOCTYPE html><html>    <head>        <meta charset=‘utf-8‘ >        <title>欢迎blue shit莅临指导&nbsp;&nbsp;</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>

DOM