原生js实现下拉框功能（支持键盘事件）
作者：继小鹏
本文主要分享了原生js实现下拉框（支持键盘事件）功能的示例代码。具有一定的参考价值，下面跟着小编一起来看下吧
话不多说，请看代码：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>倒计时-多种格式调用-原生js封装</title>
<link rel="shortcut icon" href="../public/image/favicon.ico" type="images/x-icon"/>
<link rel="icon" href="../public/image/favicon.png" type="images/png"/>
<link rel="stylesheet" type="text/css" href="../public/style/cssreset-min.css">
<link rel="stylesheet" type="text/css" href="../public/style/common.css">
<style type="text/css">
/*公共*/
html{
height:100%;
}
body, div, dl, dt, dd, ul, ol, li, h1, h2, h3, h4, h5, h6, pre, code, form, fieldset, legend, input, textarea, p, blockquote, th, td {
margin: 0;
padding: 0
}
ol, ul {
list-style: none
}
body{
position: relative;
min-height:100%;
font-size:14px;
font-family: Tahoma, Verdana,"Microsoft Yahei";
color:#333;
}
a{
text-decoration: none;
color:#333;
}
.header{
width: 960px;
padding-top: 15px;
margin: 0 auto;
line-height: 30px;
text-align: right;
}
.header a{
margin: 0 5px;
}
.main{
width:960px;
margin: 50px auto 0;
}
.code{
border:1px dashed #e2e2e2;
padding:10px 5px;
margin-bottom:25px;
}
pre {
font-family: "Microsoft Yahei",Arial,Helvetica;
white-space: pre-wrap; /*css-3*/
white-space: -moz-pre-wrap; /*Mozilla,since1999*/
white-space: -pre-wrap; /*Opera4-6*/
white-space: -o-pre-wrap; /*Opera7*/
word-wrap: break-word; /*InternetExplorer5.5+*/
}
.example{
padding-top:40px;
margin-bottom:90px;
}
.example .call{
padding:18px 5px;
background:#f0f5f8;
}
.example h2{
padding-top:20px;
margin-bottom:7px;
}
.example table {
width:100%;
table-layout:fixed;
border-collapse: collapse;
border-spacing: 0;
border: 1px solid #cee1ee;
border-left: 0;
}
.example thead {
border-bottom: 1px solid #cee1ee;
background-color: #e3eef8;
}
.example tr {
line-height: 24px;
font-size: 13px;
}
.example tr:nth-child(2n) {
background-color: #f0f5f8;
}
.example tr th,.example tr td {
border-left: 1px solid #cee1ee;
word-break: break-all;
word-wrap: break-word;
padding:0 10px;
font-weight: normal;
}
.example tr th {
color: #555;
padding-top: 2px;
padding-bottom: 2px;
text-align: left;
}
/*公共*/
.select-container {
width: 186px;
margin: 80px 0;
position: relative;
z-index: 10000;
}
.select-container .select-pose {
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; */
}
.select-pose: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.select-pose:before {
transform: rotate(180deg);
-webkit-transform: rotate(180deg);
-moz-transform: rotate(180deg);
-o-transform: rotate(180deg);
-ms-transform: rotate(180deg);
}
.select-container .select-content {
width: 184px;
border: 1px solid #333333;
background-color: #ffffff;
position: absolute;
z-index: 20000;
margin-top: -1px;
display: none;
overflow: hidden;
}
.select-list{
cursor: pointer;
height: 24px;
line-height: 24px;
padding-left: 10px;
}
</style>
<script type="text/javascript">
/*封装代码*/
(function() {
var Select = function(el, opts) {
var self = this;
var defaults = {
before: '#fff',
after:'#ccc'
}
opts = opts || {};
for (var w in defaults) {
if ("undefined" == typeof opts[w]) {
opts[w] = defaults[w];
}
}
this.params = opts;
this.container = r(el);
if (this.container.length > 1) {
var x = [];
return this.container.each(function() {
x.push(new Select(this, opts))
}), x
}
this.containers=this.container[0];
this.pose=this.container.find(".select-pose")[0];
this.content=this.container.find(".select-content")[0];
this.list=this.container.find(".select-list");
this.index=-1;
this.init();
}
Select.prototype = {
//初始化
init: function() {
var self = this;
this.page();
this.event();
this.mover();
},
event:function(){
var self = this;
self.pose.addEventListener('click', function(e) {
e = e || window.event;
e.stopPropagation ? e.stopPropagation() : e.cancelBubble = true;
var oSrc = e.srcElement || e.target;
if(oSrc.className.indexOf('extended') > -1){
self.resetM();
}else{
oSrc.classList.add("extended");
self.content.style.display = "block";
}
}, false);
},
//鼠标经过list
mover:function(){
var self = this;
var list=this.list;
for (var i = 0; i < list.length; i++) {
!function(i){
list[i].addEventListener('mouseover', function(e) {
self.resetA();
this.style.background = self.params.after;
self.index=i;
}, false);
}(i)
list[i].addEventListener('click', function(e) {
self.pose.innerHTML = this.innerHTML;
}, false);
}
},
resetA:function(){
var self = this;
var list=this.list;
for (var i = 0; i < list.length; i++) {
list[i].style.background = self.params.before;
}
},
resetM:function(){
var self = this;
self.content.style.display = "none";
self.pose.classList.remove("extended");
self.resetA();
},
// 点击页面空白处时
page:function(){
var self = this;
document.addEventListener('click', function(e) {
self.resetM();
}, false);
document.addEventListener('keydown', function(e) {
e = e || window.event;
var keyVel=e.keyCode;
if (keyVel == 38 || keyVel == 37) {
e.preventDefault ? e.preventDefault() : e.returnValue = false;//取消事件默认行为
self.index--;
if (self.index < 0) {
self.index = self.list.length-1;
}
self.resetA();
self.list[self.index].style.backgroundColor = self.params.after;
} else if (keyVel == 39 || keyVel == 40) {
e.preventDefault ? e.preventDefault() : e.returnValue = false;//取消事件默认行为
self.index++;
if (self.index > self.list.length-1) {
self.index = 0;
}
self.resetA();
self.list[self.index].style.backgroundColor = self.params.after;
}else if(keyVel == 13 && self.index != -1){
e.preventDefault ? e.preventDefault() : e.returnValue = false;
self.pose.innerHTML = self.list[self.index].innerHTML;
self.index = -1;
self.resetA();
self.resetM();
}
}, false);
},
}
var r = (function() {
var e = function(e) {
var a = this,
t = 0;
for (t = 0; t < e.length; t++) {
a[t] = e[t];
}
return a.length = e.length, this
};
e.prototype = {
addClass: function(e) {
if ("undefined" == typeof e) return this;
for (var a = e.split(" "), t = 0; t < a.length; t++)
for (var r = 0; r < this.length; r++) this[r].classList.add(a[t]);
return this
},
each: function(e) {
for (var a = 0; a < this.length; a++) e.call(this[a], a, this[a]);
return this
},
html: function(e) {
if ("undefined" == typeof e) return this[0] ? this[0].innerHTML : void 0;
for (var a = 0; a < this.length; a++) this[a].innerHTML = e;
return this
},
find: function(a) {
for (var t = [], r = 0; r < this.length; r++)
for (var i = this[r].querySelectorAll(a), s = 0; s < i.length; s++) t.push(i[s]);
return new e(t)
},
append: function(a) {
var t, r;
for (t = 0; t < this.length; t++)
if ("string" == typeof a) {
var i = document.createElement("div");
for (i.innerHTML = a; i.firstChild;) this[t].appendChild(i.firstChild)
} else if (a instanceof e)
for (r = 0; r < a.length; r++) this[t].appendChild(a[r]);
else this[t].appendChild(a);
return this
},
}
var a = function(a, t) {
var r = [],
i = 0;
if (a && !t && a instanceof e) {
return a;
}
if (a) {
if ("string" == typeof a) {
var s, n, o = a.trim();
if (o.indexOf("<") >= 0 && o.indexOf(">") >= 0) {
var l = "div";
for (0 === o.indexOf("<li") && (l = "ul"), 0 === o.indexOf("<tr") && (l = "tbody"), (0 === o.indexOf("<td") || 0 === o.indexOf("<th")) && (l = "tr"), 0 === o.indexOf("<tbody") && (l = "table"), 0 === o.indexOf("<option") && (l = "select"), n = document.createElement(l), n.innerHTML = a, i = 0; i < n.childNodes.length; i++) r.push(n.childNodes[i])
} else
for (s = t || "#" !== a[0] || a.match(/[ .<>:~]/) ? (t || document).querySelectorAll(a) : [document.getElementById(a.split("#")[1])], i = 0; i < s.length; i++) s[i] && r.push(s[i])
} else if (a.nodeType || a === window || a === document) {
r.push(a);
} else if (a.length > 0 && a[0].nodeType) {
for (i = 0; i < a.length; i++) {
r.push(a[i]);
}
}
}
return new e(r)
};
return a;
}())
window.select = Select;
})()
/*封装代码*/
</script>
</head>
<body>
<div class="header">
<a href="https://github.com/huanghanzhilian/widget" target="_blank">项目地址</a>
<a href="/widget/">返回首页</a>
</div>
<div class="main">
<div class="select-container" id="select1">
<cite class="select-pose">请选择分类</cite>
<ul class="select-content">
<li class="select-list">选项一</li>
<li class="select-list">选项二</li>
<li class="select-list">选项三</li>
<li class="select-list">选项四</li>
</ul>
</div>
<script type="text/javascript">
new select("#select1");
</script>
<div class="code">
<p>
支持键盘事件,执行默认参数,鼠标点击分类显示,鼠标经过list执行默认参数
</p>
<p>new select("#select1");</p>
</div>
<div class="example">
<div class="call">
<h1>调用方法：</h1>
<p>new select(selector,{options});</p>
</div>
<h2>options参数</h2>
<table>
<thead>
<tr>
<th width="150">参数</th>
<th width="100">默认值</th>
<th>说明</th>
</tr>
</thead>
<tbody>
<tr>
<td>before</td>
<td>'#fff'</td>
<td>鼠标经过list初始化颜色色值</td>
</tr>
<tr>
<td>after</td>
<td>'#ccc'</td>
<td>鼠标经过list颜色色值</td>
</tr>
</tbody>
</table>
</div>
</div>
</body>
</html>
以上就是本文的全部内容，希望本文的内容对大家的学习或者工作能带来一定的帮助，同时也希望多多支持脚本之家！