How do I check if a cookie exists?

Question

What's a good way to check if a cookie exist?

Conditions:

Cookie exists if

cookie1=;cookie1=345534; //or cookie1=345534;cookie1=; //or cookie1=345534; 

Cookie doesn't exist if

cookie=; //or <blank> 

Answer 1

You can call the function getCookie with the name of the cookie you want, then check to see if it is = null.

function getCookie(name) {     var dc = document.cookie;     var prefix = name + "=";     var begin = dc.indexOf("; " + prefix);     if (begin == -1) {         begin = dc.indexOf(prefix);         if (begin != 0) return null;     }     else     {         begin += 2;         var end = document.cookie.indexOf(";", begin);         if (end == -1) {         end = dc.length;         }     }     // because unescape has been deprecated, replaced with decodeURI     //return unescape(dc.substring(begin + prefix.length, end));     return decodeURI(dc.substring(begin + prefix.length, end)); }   function doSomething() {     var myCookie = getCookie("MyCookie");      if (myCookie == null) {         // do cookie doesn't exist stuff;     }     else {         // do cookie exists stuff     } } 

Answer 2

I have crafted an alternative non-jQuery version:

document.cookie.match(/^(.*;)?\s*MyCookie\s*=\s*[^;]+(.*)?$/) 

It only tests for cookie existence. A more complicated version can also return cookie value:

value_or_null = (document.cookie.match(/^(?:.*;)?\s*MyCookie\s*=\s*([^;]+)(?:.*)?$/)||[,null])[1] 

Put your cookie name in in place of MyCookie.