How to get the value of cookie

How to get the cookie value: First get all the cookie values ​​through [document.cookie]; then because you get a string with all the values ​​together, you can use the split function to split the string into an array; Finally, determine whether there is a cookie name in the array, and if so, just take it out.

The following are two ways to get the value in the cookie:

Method 1:

let allcookies = document.cookie;function getCookie(cookie_name){
    var allcookies = document.cookie;    var cookie_pos = allcookies.indexOf(cookie_name);   //索引的长度

    // 如果找到了索引，就代表cookie存在，
    // 反之，就说明不存在。
    if (cookie_pos != -1)
    {        // 把cookie_pos放在值的开始，只要给值加1即可。
        cookie_pos += cookie_name.length + 1;      //这里容易出问题，所以请大家参考的时候自己好好研究一下
        var cookie_end = allcookies.indexOf(";", cookie_pos);        if (cookie_end == -1)
        {
            cookie_end = allcookies.length;
        }        var value = unescape(allcookies.substring(cookie_pos, cookie_end));         
//这里就可以得到你想要的cookie的值了。。。
    }    return value;
}// 调用函数let  cookie_val = getCookie(cookie的名字);

Method 2

function getCookie(cname){
  var name = cname + "=";  var ca = document.cookie.split(&#39;;&#39;);  for(var i=0; i<ca.length; i++) 
  {    var c = ca[i].trim();    if (c.indexOf(name)==0) return c.substring(name.length,c.length);
  }  return "";
}// 调用函数let  cookie_val = getCookie(cookie的名字);

Principle:

(1) Get all cookie values ​​through document.cookie, Get a string containing all values ​​of a cookie.
(2) Because all cookies are separated by semicolons, use split(‘;’) to split the string into an array and save it.
(3) Determine whether each item in the array contains the cookie name. If so, just take out the corresponding value.

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