Broken string in cookie after ampersand (javascript)

Question

I have a slight problem in that the string I'm reading from a cookie is broken after the ampersand. So for example the string "hello & world" would just display "hello ". It is a string that is a short code, and converted to something more meaningful using a switch function, and then displayed within a text box. The switch function works fine, but obviously if it is not reading the full string from the cookie in the first place, then it won't be able to locate the short code within the switch function.

I am currently using the following code to read the cookie...

document.example.textfield.value = switchFunction(unescape(coalesce($_GET['example'],readCookie('_cookie'))));

If you need me to supply anymore information then please let me know. This is my first post here, so apologies in advance if anything is wrong or unclear.

Thanks For your help.

EDIT

The switchFunction looks like this..

function SwitchFuntion(Code){
    switch(Code){
       case 'text & text, Text' : return 'new meaningful text'; break;
    }
}

etc....

The readCookie function is like this...

function readCookie(name) {
    var nameEQ = name + "=";
    var ca = document.cookie.split(';');
    for(var i=0;i < ca.length;i++) {
        var c = ca[i];
        while (c.charAt(0)==' ') c = c.substring(1,c.length);
        if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
    }
    return null;
}

Can you post an example query string? It's likely that you're not encoding it properly - i.e. `myfile.htm?foo=bar&s` instead of `myfile.htm?foo=bar%26s`. — Dominic Rodger, Nov 08 '10 at 16:33
Sure. It's not actually a URL and it's not possible for me to edit this value as it's stored in a pretty secure database, but it takes the format of "text & text" (not &) — user500879, Nov 08 '10 at 16:36
I think this cannot be answered without knowledge of switchFunction,coalesce,$_GET['example'],readCookie--to many unknown quantities — Dr.Molle, Nov 08 '10 at 17:20
Ah sorry, ignore coalesce and $_GET['example'].. coalesce basically reads the value of the strings in ($_GET['example'] and readCookie('_cookie') ) and returns the value that is not null. I will edit the original post now to show the readCookie, and the switchFuntion. — user500879, Nov 08 '10 at 17:32

score 4 · Answer 1 · edited May 23 '17 at 12:04

I think I have run into a similar problem in an ASP.NET MVC app.

When I save a string containing ampersands to a cookie name/value pair it actually gets split into a series of name/value pairs

e.g. attempting to save ("value","cookiedata123&book=2&page=0") will result in 3 name value pairs being created "value"="cookiedata123"; "book"="2"; and "page"="0".

I have resolved this by URL Encoding the value just before writing to the cookie and URL Decoding it as soon as I read it out. In .net the calls look like this:

// Encode
return System.Web.HttpUtility.UrlEncode(cookieData);

// Decode
return System.Web.HttpUtility.UrlDecode(encodedCookieData);

That takes care of any ampersands, equals signs etc that can cause problems. See this post here for info on characters that are allowed in cookies. Allowed characters in cookies

Broken string in cookie after ampersand (javascript)

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