由于下拉框的条数有几十个，于是打算找一个可以搜索查找功能的下拉框，刚开始在网上看了几个，都是有浏览器兼容性问题，后来看到这个“带搜索框的jQuery下拉框美化插件 searchable”，看演示代码简单易用，支持多个浏览器。
不过在使用过程中碰到了几个问题，先后解决了。
1、多个下拉框放在一起会出现遮挡的问题，原文评论有个解决方法：
在jquery.searchableSelect.js文件里面的代码里面加上下面2行带注释的代码
show: function() {
this.dropdown.removeClass('searchable-select-hide');
this.input.focus();
this.status = 'show';
this.setPriviousAndNextVisibility();
this.dropdown.css('z-index', 100); //打开下拉列表时调高z-index层级
}, hide: function() {
if (!(this.status === 'show')) return;
if (this.items.find(':not(.searchable-select-hide)').length === 0) this.input.val('');
this.dropdown.addClass('searchable-select-hide');
this.searchableElement.trigger('focus');
this.status = 'hide';
this.dropdown.css('z-index', 1); //关闭下拉列表时恢复z-index层级
},
2、原文用的是jquery-1.11.1.min.js，但是整个项目用的是jquery-1.7.2.js，在chrome浏览器F12调试一加载页面会出现错误信息：
Uncaught TypeError: $.expr.createPseudo is not a function
$(...).searchableSelect is not a function
点进去提示$.expr.createPseudo有语法错误
猜测是jquery版本问题，果然，搜索了一下，$.expr.createPseudo是jquery1.8.1版本以上支持的。
于是修改了下代码，把下面代码
$.expr[":"].searchableSelectContains = $.expr.createPseudo(function(arg) {
return function( elem ) {
return $(elem).text().toUpperCase().indexOf(arg.toUpperCase()) >= 0;
};
});
修改为下面就解决：
$.expr[":"].searchableSelectContains = function(obj,index,meta){
return $(obj).text().toUpperCase().indexOf(meta[3].toUpperCase()) >= 0;
};
3、第2个问题解决后，发现在删除搜索框文字为空时，chrome调试窗口有异常，并且下拉框不会恢复原来的下拉选项
调试是下面这句代码有问题（如果是demo中的jquery-1.11.1.min.js版本，则不存在此问题）
this.items.find('.searchable-select-item:searchableSelectContains('+text+')').removeClass('searchable-select-hide');
解决方法是加一个是否为空的判断：
if(text != ''){
this.items.find('.searchable-select-item:searchableSelectContains('+text+')').removeClass('searchable-select-hide');
}else{
this.items.find('.searchable-select-item').removeClass('searchable-select-hide');
}
4、把功能整合到项目时，发现下拉框里面的搜索框被拉长变形了，chromeF12调试窗口能看到搜索框的样式有删除线，即被优先级更高的样式替换了。
解决方法是修改jquery.searchableSelect.css里面的样式，加一个!important提高优先级
.searchable-select-input {
margin-top: 5px;
border: 1px solid #ccc!important;
outline: none;
padding: 4px;
width: 100%!important;
box-sizing: border-box;
}
附，修改后的代码：
demo.html
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8">
<title>带搜索框的jQuery下拉框美化插件 searchableSelect</title>
<link href="jquery.searchableSelect.css" rel="stylesheet" type="text/css">
<script src="jquery-1.7.2.js"></script>
<script src="jquery.searchableSelect.js"></script>
</head>
<body>
<select id="se1">
<option value="">请选择</option>
<option value="jQuery插件库">jQuery插件库</option>
<option value="BlackBerry">BlackBerry</option>
<option value="device">device</option>
<option value="with">with</option>
<option value="entertainment">entertainment</option>
<option value="and">and</option>
<option value="social">social</option>
<option value="networking">networking</option>
<option value="apps">apps</option>
<option value="or">or</option>
<option value="apps">apps</option>
<option value="that">that</option>
</select>
<input type="button" value="test" onclick="var v = $('#se1').val();alert(v);" />
<script>
$(function(){
$('#se1').searchableSelect();
});
</script>
</body>
</html>
jquery.searchableSelect.js
// Author: David Qin
// E-mail: david@hereapp.cn
// Date: 2014-11-05 (function($){ //jQuery1.8.1以上版本使用
// a case insensitive jQuery :contains selector
/*$.expr[":"].searchableSelectContains = $.expr.createPseudo(function(arg) {
return function( elem ) {
return $(elem).text().toUpperCase().indexOf(arg.toUpperCase()) >= 0;
};
});*/ $.expr[":"].searchableSelectContains = function(obj,index,meta){
return $(obj).text().toUpperCase().indexOf(meta[3].toUpperCase()) >= 0;
}; $.searchableSelect = function(element, options) {
this.element = element;
this.options = options || {};
this.init(); var _this = this; this.searchableElement.click(function(event){
// event.stopPropagation();
_this.show();
}).on('keydown', function(event){
if (event.which === 13 || event.which === 40 || event.which == 38){
event.preventDefault();
_this.show();
}
}); $(document).on('click', null, function(event){
if(_this.searchableElement.has($(event.target)).length === 0)
_this.hide();
}); this.input.on('keydown', function(event){
event.stopPropagation();
if(event.which === 13){ //enter
event.preventDefault();
_this.selectCurrentHoverItem();
_this.hide();
} else if (event.which == 27) { //ese
_this.hide();
} else if (event.which == 40) { //down
_this.hoverNextItem();
} else if (event.which == 38) { //up
_this.hoverPreviousItem();
}
}).on('keyup', function(event){
if(event.which != 13 && event.which != 27 && event.which != 38 && event.which != 40)
_this.filter();
})
} var $sS = $.searchableSelect; $sS.fn = $sS.prototype = {
version: '0.0.1'
}; $sS.fn.extend = $sS.extend = $.extend; $sS.fn.extend({
init: function(){
var _this = this;
this.element.hide(); this.searchableElement = $('<div tabindex="0" class="searchable-select"></div>');
this.holder = $('<div class="searchable-select-holder"></div>');
this.dropdown = $('<div class="searchable-select-dropdown searchable-select-hide"></div>');
this.input = $('<input type="text" class="searchable-select-input" />');
this.items = $('<div class="searchable-select-items"></div>');
this.caret = $('<span class="searchable-select-caret"></span>'); this.scrollPart = $('<div class="searchable-scroll"></div>');
this.hasPrivious = $('<div class="searchable-has-privious">...</div>');
this.hasNext = $('<div class="searchable-has-next">...</div>'); this.hasNext.on('mouseenter', function(){
_this.hasNextTimer = null; var f = function(){
var scrollTop = _this.items.scrollTop();
_this.items.scrollTop(scrollTop + 20);
_this.hasNextTimer = setTimeout(f, 50);
} f();
}).on('mouseleave', function(event) {
clearTimeout(_this.hasNextTimer);
}); this.hasPrivious.on('mouseenter', function(){
_this.hasPriviousTimer = null; var f = function(){
var scrollTop = _this.items.scrollTop();
_this.items.scrollTop(scrollTop - 20);
_this.hasPriviousTimer = setTimeout(f, 50);
} f();
}).on('mouseleave', function(event) {
clearTimeout(_this.hasPriviousTimer);
}); this.dropdown.append(this.input);
this.dropdown.append(this.scrollPart); this.scrollPart.append(this.hasPrivious);
this.scrollPart.append(this.items);
this.scrollPart.append(this.hasNext); this.searchableElement.append(this.caret);
this.searchableElement.append(this.holder);
this.searchableElement.append(this.dropdown);
this.element.after(this.searchableElement); this.buildItems();
this.setPriviousAndNextVisibility();
}, filter: function(){
var text = this.input.val();
this.items.find('.searchable-select-item').addClass('searchable-select-hide');
if(text != ''){
this.items.find('.searchable-select-item:searchableSelectContains('+text+')').removeClass('searchable-select-hide');
}else{
this.items.find('.searchable-select-item').removeClass('searchable-select-hide');
}
if(this.currentSelectedItem.hasClass('searchable-select-hide') && this.items.find('.searchable-select-item:not(.searchable-select-hide)').length > 0){
this.hoverFirstNotHideItem();
} this.setPriviousAndNextVisibility();
}, hoverFirstNotHideItem: function(){
this.hoverItem(this.items.find('.searchable-select-item:not(.searchable-select-hide)').first());
}, selectCurrentHoverItem: function(){
if(!this.currentHoverItem.hasClass('searchable-select-hide'))
this.selectItem(this.currentHoverItem);
}, hoverPreviousItem: function(){
if(!this.hasCurrentHoverItem())
this.hoverFirstNotHideItem();
else{
var prevItem = this.currentHoverItem.prevAll('.searchable-select-item:not(.searchable-select-hide):first')
if(prevItem.length > 0)
this.hoverItem(prevItem);
}
}, hoverNextItem: function(){
if(!this.hasCurrentHoverItem())
this.hoverFirstNotHideItem();
else{
var nextItem = this.currentHoverItem.nextAll('.searchable-select-item:not(.searchable-select-hide):first')
if(nextItem.length > 0)
this.hoverItem(nextItem);
}
}, buildItems: function(){
var _this = this;
this.element.find('option').each(function(){
var item = $('<div class="searchable-select-item" data-value="'+$(this).attr('value')+'">'+$(this).text()+'</div>'); if(this.selected){
_this.selectItem(item);
_this.hoverItem(item);
} item.on('mouseenter', function(){
$(this).addClass('hover');
}).on('mouseleave', function(){
$(this).removeClass('hover');
}).click(function(event){
event.stopPropagation();
_this.selectItem($(this));
_this.hide();
}); _this.items.append(item);
}); this.items.on('scroll', function(){
_this.setPriviousAndNextVisibility();
})
},
show: function(){
this.dropdown.removeClass('searchable-select-hide');
this.input.focus();
this.status = 'show';
this.setPriviousAndNextVisibility();
this.dropdown.css('z-index', 100); //打开下拉列表时调高z-index层级
}, hide: function(){
if(!(this.status === 'show'))
return; if(this.items.find(':not(.searchable-select-hide)').length === 0)
this.input.val('');
this.dropdown.addClass('searchable-select-hide');
this.searchableElement.trigger('focus');
this.status = 'hide';
this.dropdown.css('z-index', 1); //关闭下拉列表时恢复z-index层级
}, hasCurrentSelectedItem: function(){
return this.currentSelectedItem && this.currentSelectedItem.length > 0;
}, selectItem: function(item){
if(this.hasCurrentSelectedItem())
this.currentSelectedItem.removeClass('selected'); this.currentSelectedItem = item;
item.addClass('selected'); this.hoverItem(item); this.holder.text(item.text());
var value = item.data('value');
this.holder.data('value', value);
this.element.val(value); if(this.options.afterSelectItem){
this.options.afterSelectItem.apply(this);
}
}, hasCurrentHoverItem: function(){
return this.currentHoverItem && this.currentHoverItem.length > 0;
}, hoverItem: function(item){
if(this.hasCurrentHoverItem())
this.currentHoverItem.removeClass('hover'); if(item.outerHeight() + item.position().top > this.items.height())
this.items.scrollTop(this.items.scrollTop() + item.outerHeight() + item.position().top - this.items.height());
else if(item.position().top < 0)
this.items.scrollTop(this.items.scrollTop() + item.position().top); this.currentHoverItem = item;
item.addClass('hover');
}, setPriviousAndNextVisibility: function(){
if(this.items.scrollTop() === 0){
this.hasPrivious.addClass('searchable-select-hide');
this.scrollPart.removeClass('has-privious');
} else {
this.hasPrivious.removeClass('searchable-select-hide');
this.scrollPart.addClass('has-privious');
} if(this.items.scrollTop() + this.items.innerHeight() >= this.items[0].scrollHeight){
this.hasNext.addClass('searchable-select-hide');
this.scrollPart.removeClass('has-next');
} else {
this.hasNext.removeClass('searchable-select-hide');
this.scrollPart.addClass('has-next');
}
}
}); $.fn.searchableSelect = function(options){
this.each(function(){
var sS = new $sS($(this), options);
}); return this;
}; })(jQuery);
jquery.searchableSelect.css
/*
Author: David Qin
E-mail: david@hereapp.cn
Date: 2014-11-05
*/ .searchable-select-hide {
display: none;
} .searchable-select {
display: inline-block;
min-width: 130px;
font-size: 14px;
line-height: 1.428571429;
color: #555;
vertical-align: middle;
position: relative;
outline: none;
} .searchable-select-holder{
padding: 2px;
background-color: #fff;
background-image: none;
border: 1px solid #ccc;
border-radius: 2px;
min-height: 30px;
box-sizing: border-box;
-webkit-box-shadow: inset 0 1px 1px rgba(0,0,0,0.075);
box-shadow: inset 0 1px 1px rgba(0,0,0,0.075);
-webkit-transition: border-color ease-in-out .15s,box-shadow ease-in-out .15s;
transition: border-color ease-in-out .15s,box-shadow ease-in-out .15s;
} .searchable-select-caret {
position: absolute;
width: 0;
height: 0;
box-sizing: border-box;
border-color: black transparent transparent transparent;
top: 0;
bottom: 0;
border-style: solid;
border-width: 5px;
margin: auto;
right: 10px;
} .searchable-select-dropdown {
position: absolute;
background-color: #fff;
border: 1px solid #ccc;
border-bottom-left-radius: 4px;
border-bottom-right-radius: 4px;
padding: 4px;
border-top: none;
top: 28px;
left: 0;
right: 0;
} .searchable-select-input {
margin-top: 5px;
border: 1px solid #ccc;
outline: none;
padding: 4px;
width: 100%;
box-sizing: border-box;
width: 100%;
} .searchable-scroll {
margin-top: 4px;
position: relative;
} .searchable-scroll.has-privious {
padding-top: 16px;
} .searchable-scroll.has-next {
padding-bottom: 16px;
} .searchable-has-privious {
top: 0;
} .searchable-has-next {
bottom: 0;
} .searchable-has-privious, .searchable-has-next {
height: 16px;
left: 0;
right: 0;
position: absolute;
text-align: center;
z-index: 10;
background-color: white;
line-height: 8px;
cursor: pointer;
} .searchable-select-items {
max-height: 400px;
overflow-y: scroll;
position: relative;
} .searchable-select-items::-webkit-scrollbar {
display: none;
} .searchable-select-item {
padding: 5px 5px;
cursor: pointer;
min-height: 30px;
box-sizing: border-box;
transition: all 1s ease 0s;
} .searchable-select-item.hover { background: #555;
color: white;
} .searchable-select-item.selected {
background: #28a4c9;
color: white;
}