(function($){
$.fn.autoMail = function(options){ 
var autoMail = $(this); 
var _value   = ''; 
var _index   = -1; 
var _width   = autoMail.outerWidth(); 
var _height  = autoMail.outerHeight(); 
var _left= autoMail.offset().left; 
var _top = autoMail.offset().top; 
autoMail.defaults = { 
deValue : '请输入邮箱地址', 
textCls : 'text-gray', 
listCls : 'list-mail', 
listTop : 1, 
mailArr  : ["qq.com","gmail.com","126.com","163.com","hotmail.com","yahoo.com","yahoo.com.cn","live.com","sohu.com","sina.com"] 
} 
//初始化 
autoMail.init = function(){ 
autoMail.vars = $.extend({},autoMail.defaults,options); 
autoMail.val(autoMail.vars.deValue).addClass(autoMail.vars.textCls); 
autoMail.click(function(event){ 
autoMail.select().removeClass(autoMail.vars.textCls); 
if(autoMail.val() != autoMail.vars.deValue){ 
autoMail.add(); 
autoMail.order(_value); 
autoMail.list.find('.item').each(function(){ 
if($(this).text() == autoMail.val()){ 
$(this).siblings('.item').removeClass('select'); 
$(this).addClass('select'); 
return false; 
} 
}) 
} 
event.stopPropagation(); 
}) 
autoMail.blur(function(event){ 
if(autoMail.val() == '' || autoMail.val() == autoMail.vars.deValue){ 
alert(autoMail.val()) 
autoMail.val(autoMail.vars.deValue).addClass(autoMail.vars.textCls); 
} 
}) 
//文本域键盘松开事件 
autoMail.keyup(function(event){ 
if($(autoMail.list).length == 0){ 
autoMail.add(); 
} 
if(autoMail.list.length > 0){ 
var keyCode = event.keyCode; 
//alert(keyCode) 
switch(keyCode){ 
case 13: 
autoMail.remove(); 
autoMail.blur(); 
break; 
case 38: 
_index--; 
if(_index < 0){ 
_index = 0; 
} 
autoMail.keyOperate(_index); 
break; 
case 40: 
_index++; 
if(_index > $('.item',autoMail.list).length - 1){ 
_index = ('.item',autoMail.list).length - 1 
} 
autoMail.keyOperate(_index); 
break; 
default: 
if(autoMail.val().indexOf('@') < 0){ 
_value = autoMail.val(); 
autoMail.order(_value);  
} 
}   
} 
}) 
$(document).click(function(){ 
if($(autoMail.list).length > 0){ 
autoMail.remove(); 
autoMail.blur(); 
} 
}) 
} 
//创建列表 
autoMail.create = function(){ 
var li = ''; 
for(var i = 0; i < autoMail.vars.mailArr.length; i++){ 
li += '<li class="item">'+ '<span class="style">' + '@' + autoMail.vars.mailArr[i] + '</span>' + '</li>'; 
} 
autoMail.list = $('<div class="'+ autoMail.vars.listCls +'"><ul>'+ li +'</ul></div>'); 
autoMail.list.css({ 
'position' : 'absolute', 
'left' : _left, 
'top'  : _top + _height + autoMail.vars.listTop, 
'min-width': _width 
}) 
autoMail.list.appendTo($('body')); 
//邮箱列表绑定事件 
autoMail.list.find('.item').click(function(event){ 
autoMail.getVal($(this)); 
autoMail.remove(); 
event.stopPropagation(); 
}) 
autoMail.list.find('.item').hover( 
function(){ $(this).addClass('hover'); }, 
function(){ $(this).removeClass('hover'); } 
) 
return autoMail.list; 
} 
//
序列化列表 
autoMail.order = function(_value){ 
$('.name',autoMail.list).remove(); 
var name = $('<span class="name">'+ _value +'</span>'); 
$('.item',autoMail.list).prepend(name); 
} 
//添加列表 
autoMail.add = function(){ 
if(typeof autoMail.list == 'undefined' || autoMail.list.length < 1) autoMail.create(); 
} 
//移除列表 
autoMail.remove = function(){ 
if(autoMail.list.length > 0){ 
autoMail.list.remove(); 
delete autoMail.list; 
} 
} 
//获取值 
autoMail.getVal = function(obj){ 
if($('.name',obj).text() != ''){ 
var selectValue = obj.text(); 
autoMail.val(selectValue);   
}else{ 
return false; 
} 
} 
//键盘操作 
autoMail.keyOperate = function(_index){ 
$('.item',autoMail.list).eq(_index).addClass('hover').siblings('.item').removeClass('hover'); 
autoMail.val($('.item',autoMail.list).eq(_index).text()); 
} 
//开始初始话动作... 
autoMail.init(); 
} 
})(jQuery)
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>jquery 邮箱自动补全 —— www.jb200.com</title>
<script type="text/
javascript" src="./jquery.js"></script>
<script type="text/javascript" src="./autoMail.js"></script>
<script type="text/javascript">
$(function(){
$('.automail').autoMail();
})  
</script>
<style type="text/css">
*{padding: 0; margin: 0;}
body{font-family: "微软雅黑"; color: #333; font-size: 12px;}
ul{list-style: none;}
input{ width: 180px; height: 16px; 
line-height: 16px; margin: 100px; padding: 4px; border: 1px solid #aaa; font-size: 12px; font-family: "微软雅黑"; }
.list-mail ul{ border: 1px solid #aaa; line-heihgt: 24px; padding: 6px; }
.list-mail li{ cursor: pointer; padding: 2px 3px; margin-bottom: 2px; }
.list-mail .name{ color: #982114; }
.list-mail .hover{ background: #fefacf; }
.list-mail .select{ background: #dedaae; }
</style>
</head>
<body>
<div class="test"></div>
<input type="text" class="automail" />
</body>
</html>