javascript - pc版跳m版ok,但m版点pc版链接不能停在pc版-PHP中文网问答

pc版跳m版ok,但m版点pc版链接不能停在pc版还是再跳到m版
以下是pc端代码在<head>中

   <script type="text/javascript">
    if(window.localStorage){
        if(sessionStorage.getItem("isM")!="MOK"){
            var browser={  
                versions:function(){   
                       var u = navigator.userAgent, app = navigator.appVersion;   
                       return {
                            trident: u.indexOf("Trident") > -1,
                            presto: u.indexOf("Presto") > -1,
                            webKit: u.indexOf("AppleWebKit") > -1,
                            gecko: u.indexOf("Gecko") > -1 && u.indexOf("KHTML") == -1,
                            mobile: !!u.match(/AppleWebKit.*Mobile.*/) || !!u.match(/AppleWebKit/),
                            ios: !!u.match(/\(i[^;]+;( U;)? CPU.+Mac OS X/),
                            android: u.indexOf("Android") > -1,
                            iPhone: u.indexOf("iPhone") > -1,
                            iPad: u.indexOf("iPad") > -1,
                            webApp: u.indexOf("Safari") == -1,
                            QQbrw: u.indexOf("MQQBrowser") > -1,
                            ucLowEnd: u.indexOf("UCWEB") > -1,
                            ucSpecial: u.indexOf("rv:1.2.3.4") > -1,
                            ucweb: u.indexOf("UCBrowser") > -1,
                            Symbian: u.indexOf("Symbian") > -1,
                            ucSB: u.indexOf("Firefox/1.") > -1                
                        }
                     }()  
            };
            if (screen == undefined || screen.width < 810) {
                if (browser.versions.mobile == true || browser.versions.iPhone == true || browser.versions.ucweb == true || browser.versions.android == true || browser.versions.Symbian == true) {
                    window.location.href = "m.htm";        
                }  
            };
        }else{sessionStorage.setItem("isM", "PCOK");}    
    }
    </script>

以下是m版head中代码

<script type="text/javascript">
if(window.localStorage){sessionStorage.setItem("isM", "MOK");}
</script>

求如何实现在m版点pc版链接时能浏览pc版？