JS通过Cookie判断页面是否为首次打开

function Cookie(key,value){this.key=key;if(value!=null){this.value=escape(value);}this.expiresTime=null;this.domain=null;this.path="/";this.secure=null;}Cookie.prototype.setValue=function(value){this.value=escape(value);}Cookie.prototype.getValue=function(){return (this.value);}Cookie.prototype.setExpiresTime=function(time){this.expiresTime=time;}Cookie.prototype.getExpiresTime=function(){return this.expiresTime;}Cookie.prototype.setDomain=function(domain){this.domain=domain;}Cookie.prototype.getDomain=function(){return this.domain;}Cookie.prototype.setPath=function(path){this.path=path;}Cookie.prototype.getPath=function(){return this.path;}Cookie.prototype.Write=function(v){if(v!=null){this.setValue(v);}var ck=this.key+"="+this.value;if(this.expiresTime!=null){try{ck+=";expires="+this.expiresTime.toUTCString();;}catch(err){alert("expiresTime参数错误");}}if(this.domain!=null){ck+=";domain="+this.domain;}if(this.path!=null){ck+=";path="+this.path;}if(this.secure!=null){ck+=";secure";}document.cookie=ck;}Cookie.prototype.Read=function(){try{var cks=document.cookie.split("; ");var i=0;for(i=0;i <cks.length;i++){var ck=cks[i];var fields=ck.split("=");if(fields[0]==this.key){this.value=fields[1];return (this.value);}}return null;}catch(err){alert("cookie读取错误");return null;}}

<script type="text/javascript" src="Cookie.js"></script><script type="text/javascript" language="javascript">window.onload=function(){var ck=new Cookie("HasLoaded"); //每个页面的new Cookie名HasLoaded不能相同if(ck.Read()==null){//未加载过，Cookie内容为空alert("首次打开页面");//设置保存时间var dd = new Date();dd = new Date(dd.getYear() + 1900, dd.getMonth(), dd.getDate());dd.setDate(dd.getDate() + 365);ck.setExpiresTime(dd);ck.Write("true"); //设置Cookie。只要IE不关闭，Cookie就一直存在}else{//Cookie存在，表示页面是被刷新的alert("页面刷新");}}</script>