//写cookiesfunction setCookie(c_name, value, expiredays){ 　　　　var exdate=new Date();　　　　exdate.setTime(exdate.getTime() + expiredays*24*60*60*1000);　　　　document.cookie=c_name+ "=" + escape(value) + ((expiredays==null) ? "" : ";expires="+exdate.toGMTString()); 　　} //写cookies（设置作用域）function setCookie(name,value){var Days = 30;var exp = new Date();exp.setTime(exp.getTime() + Days*24*60*60*1000);let hostname = location.hostname.substring(location.hostname.indexOf(".")+1)  //设置为一级域名document.cookie = name + "="+ escape (value) + ";expires=" + exp.toGMTString()+";domain="+hostname+";path=/";}  //读取cookiesfunction getCookie(name){ var arr,reg=new RegExp("(^| )"+name+"=([^;]*)(;|$)");   if(arr=document.cookie.match(reg))    return (arr[2]); else  return null;} //删除cookiesfunction delCookie(name){ var exp = new Date(); exp.setTime(exp.getTime() - 1); var cval=getCookie(name); if(cval!=null)  document.cookie= name + "="+cval+";expires="+exp.toGMTString();}//删除cookies（有作用域的）function delCookie(name){var exp = new Date();var name = "access_token";exp.setTime(exp.getTime() - 1);var cval=getCookie(name);if(cval!=null){let hostname = location.hostname.substring(location.hostname.indexOf(".")+1)document.cookie= name + "='';expires="+exp.toGMTString()+";domain="+hostname+";path=/";}} //使用示例setCookie('username','Darren',30)alert(getCookie("username"));