這篇文章主要介紹了JavaScript下拉選單實例程式碼,非常不錯，具有參考借鑒價值，需要的朋友可以參考下
本文給大家分享一段實例代碼關於js實現下拉菜單功能，具體程式碼如下圖所示：
<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>下拉菜单</title>
<style type="text/css">
body,
ul,
li {
margin: 0;
padding: 0;
font-size: 13px;
}
ul,
li {
list-style: none;
}
#pselect {
width: 186px;
margin: 80px auto;
position: relative;
z-index: 10000;
}
#pselect cite {
width: 150px;
height: 24px;
line-height: 24px;
display: block;
color: #807a62;
cursor: pointer;
font-style: normal;
padding-left: 4px;
padding-right: 30px;
border: 1px solid #333333;
/*background: url(xjt.png) no-repeat right center;*/
}
cite:before {
content: '';
position: absolute;
right: 7px;
bottom: 7px;
width: 0;
height: 0;
border-width: 4px;
border-style: solid;
border-color: #888 transparent transparent transparent;
transition: all 0.2s;
-webkit-transition: all 0.2s;
-moz-transition: all 0.2s;
-o-transition: all 0.2s;
-ms-transition: all 0.2s;
transform-origin: 50% 25%;
-ms-transform-origin: 50% 25%;
-moz-transform-origin: 50% 25%;
-webkit-transform-origin: 50% 25%;
-o-transform-origin: 50% 25%;
}
.extended cite:before {
transform: rotate(180deg);
-webkit-transform: rotate(180deg);
-moz-transform: rotate(180deg);
-o-transform: rotate(180deg);
-ms-transform: rotate(180deg);
}
#pselect ul {
width: 184px;
border: 1px solid #333333;
background-color: #ffffff;
position: absolute;
z-index: 20000;
margin-top: -1px;
display: none;
}
#pselect ul li {
height: 24px;
line-height: 24px;
}
#pselect ul li a {
display: block;
height: 24px;
color: #333333;
text-decoration: none;
padding-left: 10px;
padding-right: 10px;
}
.animated {
animation-fill-mode: both;
-webkit-animation-fill-mode: both;
-moz-animation-fill-mode: both;
-o-animation-fill-mode: both;
-ms-animation-fill-mode: both;
}
.speed_fast {
animation-duration: .3s;
/*-webkit-animation-duration: 0.2s;
-moz-animation-duration: 0.2s;
-o-animation-duration: 0.2s;
-ms-animation-duration: 0.2s;*/
}
.anim_extendDown {
animation-name: extendDown;
-webkit-animation-name: extendDown;
-moz-animation-name: extendDown;
-o-animation-name: extendDown;
-ms-animation-name: extendDown;
}
@keyframes extendDown {
0% {
border-bottom-color: transparent;
height: 0;
}
100% {
border-bottom-color: #333;
height: 120px;
}
}
@-webkit-keyframes extendDown {
0% {
border-bottom-color: transparent;
height: 0;
}
100% {
border-bottom-color: #333;
height: 120px;
}
}
@-moz-keyframes extendDown {
0% {
border-bottom-color: transparent;
height: 0;
}
100% {
border-bottom-color: #333;
height: 120px;
}
}
@-o-keyframes extendDown {
0% {
border-bottom-color: transparent;
height: 0;
}
100% {
border-bottom-color: #333;
height: 120px;
}
}
@-ms-keyframes extendDown {
0% {
border-bottom-color: transparent;
height: 0;
}
100% {
border-bottom-color: #333;
height: 120px;
}
}
</style>
</head>
<body>
<p id="pselect">
<cite>请选择分类</cite>
<ul>
<li id="li">
<a href="javascript:;" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" selectid="1">ASP开发</a>
</li>
<li>
<a href="javascript:;" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" selectid="2">.NET开发</a>
</li>
<li>
<a href="javascript:;" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" selectid="3">PHP开发</a>
</li>
<li>
<a href="javascript:;" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" selectid="4">Javascript开发</a>
</li>
<li>
<a href="javascript:;" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" selectid="5">Java特效</a>
</li>
</ul>
</p>
<script type="text/javascript">
window.onload = function() {
var box = document.getElementById('pselect'),
title = box.getElementsByTagName('cite')[0],
menu = box.getElementsByTagName('ul')[0],
as = box.getElementsByTagName('a'),
index = -1;
//初始样式
function resetM() {
box.className = "";
menu.className = "";
menu.style.display = "none";
index = -1;
resetA();
}
//清空a选项样式
function resetA() {
for(var i = 0; i < as.length; i++) {
as[i].style.background = "#fff";
}
}
// 点击三角时
title.onclick = function(event) {
//阻止事件冒泡
event = event || window.event;
event.stopPropagation ? event.stopPropagation() : event.cancelBubble = true;
if(box.className == "extended") {
resetM();
} else {
box.className = "extended"; //给box加类名让三角旋转
menu.className = "animated speed_fast anim_extendDown"; //下拉菜单的下拉动画
menu.style.display = "block";
}
}
document.onkeydown = function(event) {
event = event || window.event;
if(box.className == "extended") {
if(event.keyCode == 38) { //向上键
event.preventDefault ? event.preventDefault() : event.returnValue = false;
index--;
if(index == -1) {
index = as.length - 1;
}
resetA();
as[index].style.background = "#ccc";
} else if(event.keyCode == 40) { //向下键
event.preventDefault ? event.preventDefault() : event.returnValue = false;
index++;
if(index == as.length) {
index = 0;
}
resetA();
as[index].style.background = "#ccc";
} else if(event.keyCode == 13) { //回车键
event.preventDefault ? event.preventDefault() : event.returnValue = false;
title.innerHTML = as[index].innerHTML;
resetM();
}
}
}
// 滑过滑过、离开、点击每个选项时
for(var i = 0; i < as.length; i++) {
as[i].onmouseover = function() {
resetA();
this.style.background = "#ccc";
index = this.getAttribute('selectid') - 1;
}
as[i].onclick = function() {
resetM();
title.innerHTML = this.innerHTML;
}
}
// 点击页面空白处时
document.onclick = function() {
resetM();
}
}
</script>
</body>
</html>1、要阻止事件冒泡
2、鍵盤事件，用index索引
3、透過設定類別名稱或清空類別名稱的方式為元素增加動畫和恢復原有樣式
以上所述是小編給大家介紹的JavaScript下拉選單功能實例代碼，希望對大家有所幫助，如果大家有任何疑問請給我留言，小編會及時回覆大家的。在此也非常感謝大家對PHP中文網的支持！
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