js 操作cookie，getCookie,setCookie ,removeCookie

 document.cookie = ‘name=‘+‘username‘;
    document.cookie = ‘value=‘+‘value1‘;

    var cookarr = document.cookie.replace(/\s/g,"").split(‘;‘);//将cookie的空格全部替换掉，不然会出现空格，使结果无法判断
    var havcome = false;
    for (var i=0;i<cookarr.length;i++){
        var str = cookarr[i].split(‘=‘);
        if(str[0]==‘dateam‘) {
            havcome = true;
            break
        }
    }
    console.log(document.cookie);
    console.log(havcome);
    var date = new Date();
    var day = date.getTime();
    console.log(day);
    var newday = new Date(day + 7*24*60*60*1000);//设置过期时间，这里设置为七天之后；
    var oldday = new Date(day -1);//设置删除时间，只要过期时间在设置时间之前，就可以将cookie删除；
    console.log(newday.toUTCString());
    if (!havcome){
        document.cookie = ‘dateam‘+‘=‘+‘haha‘+‘;expires=‘+newday.toUTCString();
        alert(‘欢迎你第一次来‘);
    }

    document.cookie = ‘dateam‘+‘=‘+‘haha‘+‘;expires=‘+oldday.toUTCString();//将过期时间设置为已经过去的 1 ms，则可以立即删除dateamcookie