实现EMAIL本页功能
例子：
<html>
<title>测试</title>
<body>
<script language="javascript">
function mailpage()
{
mail_str = "mailto:xxx@21cn.com?subject=推荐网页: " + document.title;
mail_str += "&body=我向你推荐这个页面，希望你喜欢！网页标题：" + document.title;
mail_str += "。请点击查看： " + location.href;
location.href = mail_str;
}
</script>
<A HREF = "javascript:mailpage()">E-mail本页</A>
