$(document).ready(function() 
{
var Oldselectvalue="";
$('#OnlineShopSelect').click(function()
{
if($('#OnlineShopSelect').val()!=Oldselectvalue){
Oldselectvalue=$('#OnlineShopSelect').val(); 

}
else
{
Oldselectvalue="";
 window.open($('#OnlineShopSelect').val());
 
 }
});

$('#OnlineShopSelect').click(function()
{
$('#OnlineShopSelect')[0].selectedIndex=0;
});


$('#OnlineShopSelect').change(function()
{
  window.open($('#OnlineShopSelect').val());
});
});


//-->
document.write("<select name='select' id='OnlineShopSelect' >");
document.write("<option value=\"http://1102283751.paipai.com/?PTAG=20012.8.4\">联想官方拍拍旗舰店</option>");
document.write("<option value=\"http://yangtian.mall.taobao.com/\">联想官方商用旗舰店</option>");
document.write("<option value=\"http://lenovo.dangdang.com/\">联想官方当当旗舰店</option>");
document.write("<option value=\"http://www.lenovomobile.com/phoneshow/sale.aspx\">联想手机，网上商城</option>");
document.write("</select>");