添加索引值
1、index索引值
2、索引值运用：图片切换实例
思路一：全部清除
思路二：消除上一个
<!DOCTYPE HTML> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <title>无标题文档</title> <style> ul { padding:0; margin:0; } li { list-style:none; } body { background:#333; } #pic { width:400px; height:500px; position:relative; margin:0 auto; background:url(img/loader_ico.gif) no-repeat center #fff; } #pic img { width:400px; height:500px; } #pic ul { width:40px; position:absolute; top:0; right:-50px; } #pic li { width:40px; height:40px; margin-bottom:4px; background:#666; } #pic .active { background:#FC3; } #pic span { top:0; } #pic p { bottom:0; margin:0; } #pic p,#pic span { position:absolute; left:0; width:400px; height:30px; line-height:30px; text-align:center; color:#fff; background:#000; } </style> <script> window.onload = function (){ var oDiv = document.getElementById('pic'); var oImg = oDiv.getElementsByTagName('img')[0]; var oSpan = oDiv.getElementsByTagName('span')[0]; var oP = oDiv.getElementsByTagName('p')[0]; var oUl = oDiv.getElementsByTagName('ul')[0]; var aLi = oUl.getElementsByTagName('li'); var arrUrl = [ 'img/1.png', 'img/2.png', 'img/3.png', 'img/4.png' ]; var arrText = [ '图片一', '图片二', '图片三', '图片四' ]; var num = 0; var oldLi = null; for( var i=0; i<arrUrl.length; i++ ){ oUl.innerHTML += '<li></li>'; } oldLi = aLi[num]; // 初始化 oImg.src = arrUrl[num]; oSpan.innerHTML = 1+num+' / '+arrUrl.length; oP.innerHTML = arrText[num]; aLi[num].className = 'active'; for( var i=0; i<aLi.length; i++ ){ aLi[i].index = i; // 索引值 aLi[i].onclick = function (){ oImg.src = arrUrl[ this.index ]; oP.innerHTML = arrText[ this.index ]; oSpan.innerHTML = 1+this.index + ' / '+arrText.length; /* <li class="active"></li> <li></li> <li></li> <li></li> */ // 思路一：先全部清空，再在当前的li元素中添加 for( var i=0; i<aLi.length; i++ ){ aLi[i].className = ''; } this.className = 'active'; /* // 思路二：先清空上个li元素的class值，再在当前的li元素中添加 oldLi.className = ''; oldLi = this; this.className = 'active'; */ }; } }; </script> </head> <body> <div id="pic"> <img src="img/1.png" /> <span>数量正在加载中……</span><!--图片的页码--> <p>文字说明正在加载中……</p><!--图片文字说明--> <ul> </ul> </div> </body> </html>图片
图片切换实例扩展
1、this引用
2、函数合并
// 初始化 function fnTab(){ oImg.src = arrUrl[num]; oSpan.innerHTML = 1+num+' / '+arrUrl.length; oP.innerHTML = arrText[num]; for( var i=0; i<aLi.length; i++ ){ aLi[i].className = ''; } aLi[num].className = 'active'; } fnTab(); //如果没有这一行，在没有点击的情况下，不会有图片出现 for( var i=0; i<aLi.length; i++ ){ aLi[i].index = i; // 索引值 aLi[i].onclick = function (){ num = this.index; fnTab(); }; }实例：QQ列表展示
<!DOCTYPE HTML> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <title>无标题文档</title> <style> ul , h2 { padding:0; margin:0; } li { list-style:none; } #list { width:240px; border:1px solid #333; margin:0 auto; } #list .lis {} #list h2 { height:30px; line-height:30px; text-indent:20px; background:url(img/ico1.gif) no-repeat 5px center #6FF; color:#000; } #list .active { background:url(img/ico2.gif) no-repeat 5px center #FF9; color:#000; } #list ul { display:none; } #list ul li { line-height:24px; border-bottom:1px solid #333; text-indent:24px; } #list ul .hover { background:#6FF; } </style> <script> window.onload = function (){ var oUl = document.getElementById('list'); var aH2 = oUl.getElementsByTagName('h2'); var aUl = oUl.getElementsByTagName('ul'); var aLi = null; var arrLi = []; for( var i=0; i<aH2.length; i++ ){ aH2[i].index = i; aH2[i].onclick = function (){ for( var i=0; i<aH2.length; i++ ){ if( i != this.index ){ aUl[i].style.display = 'none';//隐藏 aH2[i].className = ''; } } if( this.className == '' ){ aUl[this.index].style.display = 'block';//将页面元素转换为块状元素 this.className = 'active'; } else { aUl[this.index].style.display = 'none'; this.className = ''; } }; } for( var i=0; i<aUl.length; i++ ){ aLi = aUl[i].getElementsByTagName('li'); for( var j=0; j<aLi.length; j++ ){ arrLi.push( aLi[j] ); } } for( var i=0; i<arrLi.length; i++ ){ arrLi[i].onclick = function (){ for( var i=0; i<arrLi.length; i++ ){ if( arrLi[i] != this ){ arrLi[i].className = ''; } } if( this.className == '' ){ this.className = 'hover'; }else{ this.className = ''; } }; } }; </script> </head> <body> <ul id="list"> <li class="lis"> <h2>我的好友</h2> <ul> <li>张三</li> <li>张三</li> <li>张三</li> <li>张三</li> </ul> </li> <li class="lis"> <h2>我的同学</h2> <ul> <li>李四</li> <li>李四</li> <li>李四</li> <li>李四</li> <li>李四</li> </ul> </li> <li class="lis"> <h2>黑名单</h2> <ul> <li>张小三</li> <li>李小四</li> </ul> </li> </ul> </body> </html>