限制网页只在手机端中打开，网站屏蔽PC端访问JS代码，网站只允许手机端访问

<script type="text/javascript">
if(window.screen.width==0){window.location.replace("https://xxxx.com")};
var system={win:false,mac:false,xll:false};
var p = navigator.platform;
system.win=p.indexOf("Win")==0;
system.mac=p.indexOf("Mac")==0;
system.x11=(p=="X11") || (p.indexOf("Linux")==0);
if(system.win||system.mac||system.xll) {
location.replace("https://xxxx.com");
}
</script>