如何让页面只能在微信端打开？

<script type="text/javascript">
// 对浏览器的UserAgent进行正则匹配，不含有微信独有标识的则为其他浏览器
var useragent = navigator.userAgent;
if (useragent.match(/MicroMessenger/i) != 'MicroMessenger') {
// 这里警告框会阻塞当前页面继续加载
var url = window.location.href;
window.location.href = 'https://open.weixin.qq.com/connect/oauth2/authorize?appid={$_W['account']['key']}&redirect_uri='+url+'&response_type=code&scope=snsapi_base&state=YWN0PW1vZHVsZSZuYW1lPXNob3BwaW5nMiZkbz1saXN0JndlaWQ9Mg==&connect_redirect=1#wechat_redirect';
}
</script>