js cookie 实例

首先来介绍下cookie知识点：

• document.cookie 来设置cookie

• cookie.domain表示cookie的域， 控制cookie所在的域，跨域的不能访问

• cookie.path表示cookie的路经 cookie能让其path路径下的页面访问

  以下是模仿浏览器自动登录的功能，每次刷新时来检查cookie，弹出欢迎界面。

  function setCookie(name,value,days){  var d = new Date();  d.setTime(d.getTime() + (days*24*60*60*1000));  var expires = "expires=" + d.toGMTString();  document.cookie  = name + "=" + value + "; " + expires;}function getCookie(name){  var cname = name + "=";  var temp = document.cookie.split(";");  for(var i=0;i<temp.length;i++){    temp[i] = temp[i].trim();    if(temp[i].indexOf(cname) == 0){      return temp[i].substring(cname.length,temp[i].length);    }    return "";  }}function checkCookie(){  var user = getCookie("username");  if(user == ""){    user = prompt("Please enter your username:","");    if(user!="" && user!=null){      setCookie("username",user,30);    }  }    else{      alert("welcome again" + user);    }}// checkCookie();document.onload = checkCookie();