JavaScript读写Cookie的完整实现与浏览器兼容性说明

//创建cookie
function setCookie(name, value, expireday) {
 var exp = new Date();
 exp.setTime(exp.getTime() + expireday*24*60*60*1000); //设置cookie的期限
 document.cookie = name+"="+escape(value)+"; expires"+"="+exp.toGMTString();//创建cookie
}
//提取cookie中的值
function getCookie(name) {
 var cookieStr = document.cookie;
 if(cookieStr.length > 0) {
 var cookieArr = cookieStr.split(";"); //将cookie信息转换成数组
 for (var i=0; i<cookieArr.length; i++) {
  var cookieVal = cookieArr[i].split("="); //将每一组cookie(cookie名和值)也转换成数组
  if(cookieVal[0] == name) {
  return unescape(cookieVal[1]); //返回需要提取的cookie值
  }
 }
 }
}
//测试cookie
function checkCookie() {
 var cookieUser = document.getElementById("cookieUser");
 var userName = getCookie("userName");
 if(userName) {
 cookieUser.innerHTML = "您好"+userName+"，欢迎再次回来！"; 
 } else {
 var value = prompt("请输入用户名", "");
 if(value) {
  setCookie('userName', value, 1);
 } else {
  alert("请输入用户名！");
 }
 }
}

function getCookie(name) {
 var cookieStr = document.cookie;
 var cookieArr = cookieStr.match(new RegExp(name+"=[a-zA-Z0-9]*;$"));
 var cookieVal = cookieArr.split("=");
 if(cookieVal[0] == name) {
 return unescape(cookieVal[1]);
 }
}

<body onload="checkCookie()">
<p id="cookieUser"></p>
</body>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
  <head>
   <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
   <title>Cookie的读取例子</title>
   <link href="CSS/sheet.css" rel="external nofollow" rel="stylesheet" type="text/css">
<script language="javascript">
function writeCookie(){//写入cookie
 document.cookie=encodeURI("username="+document.form1.username.value);
 document.cookie=encodeURI("password="+document.form1.password1.value);
}
function readCookie(){//读取cookie
 var cookieString=decodeURI(document.cookie);//调用decodeURI函数获取Cookie
 if(cookieString.length!=0){//cookie不为空
  var cookies=cookieString.split(";");//使用字符串的split函数利用“；“分割字符串为数组，这样就把username和password分开了
  for(var i=0;i<cookies.length;i++){
   var cookieN=cookies[i].split("=");//使用字符串的split函数利用“=“分割字符串为数组，这样就把username和username的值分开了
   var cookieName=cookieN[0];//
   var cookieValue=cookieN[1];
   alert("Cookie名称为:"+cookieName+" ，值为:"+cookieValue);
 }
}else
alert("Cookie为空,请填写信息");
}
</script>
</head>
<body onload="makesnake()">
 <form action="" method="post" name="form1">
  <table >
   <tr align="right"><td>用户名：</td><td><input type="text" name="username" /></td></tr>
   <tr align="right"><td>密码：</td><td><input type="password" name="password1" /></td></tr>
   <tr align="right"><td>确认密码：</td><td><input type="password" name="password2" /></td></tr>
   <tr align="center">
    <td ><input type="button" value="写入Cookies" onClick="writeCookie();"></td>
    <td><input type="button" value="读取Cookies" onClick="readCookie();"></td></tr>
   </table>
  </form>
 </body>
</html>