Javascript document.cookie remove “name” and “value”

Question

In my Javascript I have a cookie with several names and values:

"Token=23432112233299; sessionuid=abce32343234"

From server when I download a file a Add a Cookie so the new document cookie will look:

  "Token=23432112233299; sessionuid=abce32343234; fileDownload=true"

How can I remove the fileDownload name and value from cookie and update document.cookie?

UPDATE:

This is the code I have done so far but its not working:

if (document.cookie.indexOf("fileDownload=true;") != -1) {
    document.cookie = document.cookie.replace("fileDownload=true;", "");
} else {
    document.cookie = document.cookie.replace("fileDownload=true", "");
}

Answer 1

Change the expires parameter to the elapsed date.
document.cookie = 'fileDownload = ; expires=-1';

Answer 2

    var cookieData = "fileDownload=; path=/" +"; expires=" + new Date(0).toUTCString() + ";";
    if (null) cookieData += " domain=null;";
    document.cookie = cookieData;