请大家帮忙看看，为什么这段代码有的能替换有的不能替换

正确的应该是：

DVD%E7%89%88%2B%2Bhttp%3A%2F%2Fi7.imgs.letv.com%2Fplayer%2FswfPlayer.swf%3FautoPlay%3D1%26id%3D1928231%24%24%24DVD%E7%89%88%2B%2Bbdhd%3A%2F%2F29985609%7CEB961064E957D941D3E65A11587F4442%7C%E8%B8%AE%E8%B5%B7%E8%84%9A%E5%B0%96+%E5%BE%AE%E7%94%B5%E5%BD%B1.flv

[解决办法]

<script language="javascript" runat="server">
var str=Request.Form("m_playurl");
str=eval(str + "");   //保证是String 类型
</script>
<%
Response.write str
%>