由于select修改样式不能兼容浏览器，也不能随意修改，那么就需要模拟select，给select添加皮肤了，代码如下
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<script src="js/jquery-1.8.2.min.js"></script>
<style>
*{ margin:0; padding:0; }
.mydiv{ width:350px; margin-top:100px; }
select{ margin:10px; }
/*js相关css*/
.cl{ zoom:1; }
.cl:after{ display:block; width:0; height:0; content:''; clear:both; overflow:hidden; }
.js-select-box{ position:relative; display:inline-block; }
.js-select-box ul,.js-select-box li{ list-style:none; }
.js-select-box a{ text-decoration:none; }
.js-select-tit{ cursor:pointer; width:100%; height:100%; border:1px solid #eee; height:30px; line-height:30px; }
.js-select-tit span{ display:inline-block; text-overflow:ellipsis; white-space:nowrap; margin-left:5px; height:100%; }
.js-select-tit .js-arr{ position:absolute; top:50%; margin-top:-3px; right:5px; display:inline-block; width:0; height:0; border:6px solid transparent; border-top:6px solid #aaa; }
.js-select-menu{ width:100%; border:1px solid #eee; position:absolute; top:33px; background-color:#fff; display:none; max-height:150px; overflow-y:auto; }
.js-select-menu li a{ display:block; padding:0 10px; height:25px; line-height:25px; text-overflow:ellipsis; white-space:nowrap; }
.js-select-menu li a:hover,.js-select-menu li.active a{ background-color:#f4f4f4; }
.select1{ height:40px; line-height:40px; }
</style>
</head>
<body>
<div class="mydiv cl">
<select style="width:150px;">
<option value="1">aaaa</option>
<option value="2">bbbb</option>
<option value="3">cccc</option>
</select>
<select style="width:150px;" id="select2">
<option value="21">aaaa2</option>
<option value="22">bbbb2</option>
<option value="23">cccc2</option>
<option value="24">dddd2</option>
</select>
</div>
<select style="width:120px;" class="select3">
<option value="31">aaaa3</option>
<option value="32">bbbb3</option>
</select>
<div class="cl">
<select style="width:120px;" class="select1">
<option value="11">aaaa1</option>
<option value="12">bbbb1</option>
<option value="13">cccc1</option>
<option value="14">dddd1</option>
<option value="15">eeee1</option>
<option value="16">ffff1</option>
<option value="17">gggg1</option>
<option value="18">hhhh1</option>
<option value="19">iiii1</option>
<option value="101">jjjj1</option>
<option value="102">kkkk1</option>
</select>
</div>
<script>
//创建节点
function selectFun(dom,opt){
var $dom = $(dom);
var dtw = this.dtw = $dom.outerWidth();//宽度
this.box = $('<div class="js-select-box"></div>');
this.tit = $('<div class="js-select-tit" style="width:'+(dtw-2)+'px"><i class="js-arr"></i></div>');
this.titSpan = $('<span style="width:'+(dtw-7)+'px"></span>');
this.menu = $('<div class="js-select-menu"></div>');
this.box.append(this.tit.append(this.titSpan)).append(this.menu);
this.dom = dom;
this.cfg = this.getConfig(opt);
//追加节点
if($dom.attr("data-skin") === "true"){
$dom.next("div.js-select-box").remove();
}else{
$dom.attr("data-skin","true");
}
$dom.after(this.box);
$dom.hide();
//设置样式
this.box.css({"margin-top":$dom.css("marginTop"),"margin-right":$dom.css("marginRight"),"margin-bottom":$dom.css("marginBottom"),"margin-left":$dom.css("marginLeft"),"width":dtw});
this.tit.addClass($dom.prop("className"));
$dom.prop("id") ? this.tit.prop("id",$dom.prop("id")) : "";
this.addMenu(dom);
//事件
this.bindEvent(dom);
}
var selectDom = null;
selectFun.create = function(dom,opt){
return new selectFun(dom,opt);
}
selectFun.prototype.getConfig = function(opt){
var cfg = $.extend({
val: "",//默认值
clsName: "active",//当前class
inx: 0,//已选择的索引
callback: null //返回函数
},opt || {});
return cfg;
}
selectFun.prototype.setPosition = function(sibMenu){//设置下拉位置
var wth = $(window).height();
var ty = sibMenu.offset().top;
var domth = sibMenu.outerHeight(true);
var titTh = sibMenu.siblings("div.js-select-tit").outerHeight(true);
if((ty+domth) > wth){
sibMenu.css({"top":"auto","bottom":(titTh+1)+"px"});
}else{
sibMenu.css({"top":(titTh+1)+"px","bottom":"auto"});
}
}
selectFun.prototype.addMenu = function(dom){//添加下拉
var optDoms = $(dom).find("option");
var ulDom = $("<ul></ul>");
var liDom = "";
var val = this.cfg.val;//已选择的value
for(var i=0; i<optDoms.length; i++){//创建li
if(val === ""){
this.titSpan.text(optDoms.eq(0).text());
this.cfg.inx = 0;
}else if(optDoms[i].value == val){
this.titSpan.text(optDoms.eq(i).text());
this.cfg.inx = i;
}
liDom += '<li class="js-select-items" data-val="'+optDoms[i].value+'"><a href="javascript:;">'+optDoms.eq(i).text()+'</a></li>'
}
ulDom.html(liDom);
this.menu.append(ulDom).width(this.dtw-2);//添加下拉
ulDom.find("li").eq(this.cfg.inx).addClass(this.cfg.clsName);//添加class
}
selectFun.prototype.hideEvent = function(sibMenu,selectBox){//隐藏（下拉，select框）
if(selectBox){
selectBox = sibMenu.parent("div.js-select-box");
}
sibMenu.hide().css({"top":(sibMenu.siblings("div.js-select-tit").outerHeight(true)+1)+"px","bottom":"auto"});;
selectBox.css("z-index",1);
}
selectFun.prototype.bindEvent = function(dom){
var self = this;
self.tit.click(function(){
var $tTit = $(this);
var $tp = $tTit.parent("div.js-select-box");
var sib = $tTit.siblings("div.js-select-menu");
var tpSib = $("div.js-select-box");
if(sib.is(":hidden")){
//隐藏已展开的select
var sibMenu = tpSib.find("div.js-select-menu").not(":hidden");
self.hideEvent(sibMenu,sibMenu.parents("div.js-select-box"));//隐藏
sib.show();
$tp.css("z-index",9);
self.setPosition(sib);//位置
selectDom = self;
}else{
self.hideEvent(sib,$tp);//隐藏
selectDom = null;
}
});
self.menu.on("click","li",function(){
self.setVal($(this),self.dom);
});
$(document).click(function(e){
var tag = $(e.target || window.event.srcElement);
var boxDom = $("div.js-select-box").not(":hidden");
if(tag.hasClass("js-select-box") || tag.parents("div.js-select-box").length > 0){
return;
}else{
self.hideEvent(boxDom.find("div.js-select-menu"),boxDom);//隐藏
}
});
}
selectFun.keyDownFun = function(e){
var self = selectDom;
var sib = $("div.js-select-menu").not(":hidden");
var sibTp = sib.parents("div.js-select-box");
var dom = sibTp.prev("select")[0];
var lis = sib.find("li.active");
var code = e.keyCode;
var nextOrPrev,clsName;
if(!self){
return;
}
clsName = self.cfg.clsName;
switch(code){
case 40:
nextOrPrev = self.nextOrPrevDom(lis,true);//添加class
nextOrPrev.addClass(clsName).siblings("li").removeClass(clsName);
self._scrollToItem(nextOrPrev);
break;
case 38:
nextOrPrev = self.nextOrPrevDom(lis,false);//添加class
nextOrPrev.addClass(clsName).siblings("li").removeClass(clsName);
self._scrollToItem(nextOrPrev);
break;
case 13:
self.setVal(lis,dom);
break;
case 27:
self.hideEvent(sib,sibTp);//隐藏
break;
default:break;
}
}
selectFun.prototype.nextOrPrevDom = function(curDom,isNext){
var obj = null;
if(isNext){
obj = curDom.next();
if(obj.length <= 0){
obj = curDom.parents("div.js-select-menu").find("li").eq(0);
}
}else{
obj = curDom.prev();
if(obj.length <= 0){
obj = curDom.parents("div.js-select-menu").find("li:last");
}
}
return obj;
}
selectFun.prototype._scrollToItem = function(item){
var menuDom = item.parents(".js-select-menu");
menuDom.scrollTop((menuDom.find("li").height()*item.index())/2);
};
selectFun.prototype.setVal = function(t,dom){//设置内容
var inx = t.index();
var txt = t.text();
var dataVal = t.data("val");
var tp = t.parents("div.js-select-menu");
var fn = new Function();
tp.siblings("div.js-select-tit").find("span").text(txt);
this.hideEvent(tp,tp.parent("div.js-select-box"));//隐藏
t.addClass(this.cfg.clsName).siblings("li").removeClass(this.cfg.clsName);//添加class
$(dom).find("option").eq(inx).prop("selected",true);//select赋值
if((typeof this.cfg.callback).toLowerCase() === "function"){
this.cfg.callback(dataVal,txt,inx);//已选择的：val，text，索引
}
$(dom).trigger("change");
}
$.fn.extend({
selecter : function(options){
this.each(function(i,dom){
selectFun.create(dom,options);
});
}
});
$(document).on("keydown",selectFun.keyDownFun);
$("select").selecter();
$(".select1").selecter({"callback":function(v,txt,i){
console.log(v,txt,i);
}});
$("select").change(function(){
alert($(this).val());
});
</script>
</body>
</html>
但在这在ie7上有点儿小样式问题，不过可以通过修改样式解决，从而到达自己想要的效果。
select的onchange事件的函数，可以通过callback来完成。
