cookie

1、写入cookie

document.cookie = "userId="+userid;

2、获取cookie

    var strCookie = document.cookie;
    //将多cookie切割为多个名/值对 
    var arrCookie = strCookie.split("; ");
    //遍历cookie数组，处理每个cookie对 
    for (var i = 0; i < arrCookie.length; i++) {
        var arr = arrCookie[i].split("=");
        if ("userId" == arr[0]) {
            userId = arr[1];
            break;
        }
        else{
            userId = "";
        }
    }

3、删除cookie数据

document.cookie = "userId="+"";