JS拿cookie值

/*
* name 是cookie的名字,value是cookie的值 days表示保存几天
*/
function createCookie(name,value,days){
    if(days){
        var date = new Date();
        date.setTime(date.getTime()+(days*24*60*60*1000));
        var expires ='; expires=' +date.toGMTString();
    }else{
        var expires ='';
    }
    document.cookie = name+'='+value+expires+'; path=/';
}

//取出name为name的value值
function readCookie(name){
    var nameEQ = name+'=';
    var ca = document.cookie.split(';');//其实可以用'; '分隔
   
    for(var i=0;i<ca.length;i++){
        var c = ca[i];
        while(c.chatAt(0)==' ') s.substring(1,c.length);
        if(c.indexOf(nameEQ)==0) return s.substring(nameEQ.length,c.length);
    }
    return '';
}

function eraseCookie(name){
    createCookie(name,'',-1);
}