Detailed explanation of method examples for setting and obtaining cookies in javascript

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Detailed explanation of method examples for setting and obtaining cookies in javascript_javascript skills

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May 16, 2016 pm 03:21 PM

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The example in this article describes how to set and obtain cookies in javascript. Share it with everyone for your reference, the details are as follows:

1. Set cookies

function setCookie(cookieName,cookieValue,cookieExpires,cookiePath)
{
  cookieValue = escape(cookieValue);//编码latin-1
  if(cookieExpires=="")
  {
    var nowDate = new Date();
    nowDate.setMonth(nowDate.getMonth()+6);
    cookieExpires = nowDate.toGMTString();
  }
  if(cookiePath!="")
  {
    cookiePath = ";Path="+cookiePath;
  }
  document.cookie= cookieName+"="+cookieValue+";expires="+cookieExpires+cookiePath;
}

2. Get cookies

function getCookieValue(cookieName)
{
  var cookieValue = document.cookie;
  var cookieStartAt = cookieValue.indexOf(""+cookieName+"=");
  if(cookieStartAt==-1)
  {
    cookieStartAt = cookieValue.indexOf(cookieName+"=");
  }
  if(cookieStartAt==-1)
  {
    cookieValue = null;
  }
  else
  {
    cookieStartAt = cookieValue.indexOf("=",cookieStartAt)+1;
    cookieEndAt = cookieValue.indexOf(";",cookieStartAt);
    if(cookieEndAt==-1)
    {
      cookieEndAt = cookieValue.length;
    }
    cookieValue = unescape(cookieValue.substring(cookieStartAt,cookieEndAt));//解码latin-1
  }
  return cookieValue;
}

Example:

<!doctype html>
<html>
<head>
<title>cookie</title>
<meta charset="utf-8">
<script language="javascript" type="text/javascript">
  //获取cookie
   function getCookieValue(cookieName)
  {
    var cookieValue = document.cookie;
    var cookieStartAt = cookieValue.indexOf(""+cookieName+"=");
    if(cookieStartAt==-1)
    {
      cookieStartAt = cookieValue.indexOf(cookieName+"=");
    }
    if(cookieStartAt==-1)
    {
      cookieValue = null;
    }
    else
    {
      cookieStartAt = cookieValue.indexOf("=",cookieStartAt)+1;
      cookieEndAt = cookieValue.indexOf(";",cookieStartAt);
      if(cookieEndAt==-1)
      {
        cookieEndAt = cookieValue.length;
      }
      cookieValue = unescape(cookieValue.substring(cookieStartAt,cookieEndAt));//解码latin-1
    }
    return cookieValue;
  }
  //设置cookie
  function setCookie(cookieName,cookieValue,cookieExpires,cookiePath)
  {
    cookieValue = escape(cookieValue);//编码latin-1
    if(cookieExpires=="")
    {
      var nowDate = new Date();
      nowDate.setMonth(nowDate.getMonth()+6);
      cookieExpires = nowDate.toGMTString();
    }
    if(cookiePath!="")
    {
      cookiePath = ";Path="+cookiePath;
    }
    document.cookie= cookieName+"="+cookieValue+";expires="+cookieExpires+cookiePath;
  }
  //页面加载时间处理函数
  function window_onload()
  {
    var userNameElem = document.getElementById("userName");//用户名输入框对象
    var passwordElem = document.getElementById("password");//密码输入框对象
    var currUserElem = document.getElementById("currUser");//复选框对象
    var currUser = getCookieValue("currUser");
    if(currUser!=null)
    {
      userNameElem.value=currUser;
      currUserElem.checked = true;
    }
    if(userNameElem.value!="")
    {
      passwordElem.focus();//密码输入框获得焦点
    }
    else
    {
      currUserElem.focus();//用户名输入框获得焦点
    }
  }
  //表单提交处理
  function login()
  {
    var userNameElem = document.getElementById("userName");
    var passwordElem = document.getElementById("password");
    var currUserElem = document.getElementById("currUser");
    if(userNameElem.value=="" || passwordElem.value=="")
    {
      alert("用户名或密码不能为空！");
      if(userNameElem.value=="")
      {
        userNameElem.focus();//用户名输入框获得焦点
      }
      else
      {
        passwordElem.focus();//密码输入框获得焦点
      }
      return false;
    }
    if(currUserElem.checked)
    {
      setCookie("currUser",userNameElem.value,"","");//设置cookie
    }
    else
    {
      var nowDate = new Date();//当前日期
      nowDate.setMonth(nowDate.getMonth()-2);//将cookie的过期时间设置为之前的某个日期
      cookieExpires = nowDate.toGMTString();//过期时间的格式必须是GMT日期的格式
      setCookie("userName","",cookieExpires,"");//删除一个cookie只要将过期时间设置为过去的一个时间即可
    }
    return true;
  }
</script>
<style type="text/css">
  div{
    font-size:12px;
  }
</style>
</head>
<body onload="window_onload()">
<div>
<form id="loginForm" onsubmit="return login()">
用户名：<input type="text" id="userName"><br>
密 码：<input type="password" id="password">
<input type="checkbox" id="currUser">记住用户名<br>
<input type="submit" value="登录">
</form>
</div>
</body>
</html>

Note:

Since Google Chrome only supports online-cookies for security reasons, it has no effect when tested locally. You need to upload it to the server to try.

For more information about JavaScript operating cookies, please view the special topics on this site: " Summary of knowledge related to JavaScript operating cookies " and " Summary of jQuery's cookie operating skills "

I hope this article will be helpful to everyone in JavaScript programming.

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