Which date formats can I use when specifying the expiry date when setting a cookie?

cookies, javascript

Solution

Based on testing and further reading into this, a date in a UTC/GMT format is required by cookies e.g. Sun, 15 Jul 2012 00:00:01 GMT

Therefore any dates in other formats such as 15 Jul 2012, or 15/Jul/2012, or 07/15/2012, have to be passed as a `new Date` object and then through the `toUTCString()` or the `toGMTString()` function.

therefore I have edited my function to the following:

function setCookie(name, value, exdate) {
    //If exdate exists then pass it as a new Date and convert to UTC format
    (exdate) && (exdate = new Date(exdate).toUTCString());
    var c_value = escape(value) + ((exdate === null || exdate === undefined) ? "" : "; expires=" + exdate);
    document.cookie = name + "=" + c_value;
};

Problem

I am using a function which sets a cookie. This function allows the cookie name, the cookie value and an additional expiry date of the cookie to be passed into it. ``` function setCookie(name, value, exdate) { var c_value = escape(value) + ((exdate === null || exdate === undefined) ? "" : "; expires=" + exdate); document.cookie = name + "=" + c_value; }; ``` Usage: ``` setCookie("my-cookie-name","my-value","Sun, 15 Jul 2012 00:00:01 GMT"); ``` I have used the function with the date format above and believe it is cross browser compatible as I have tested if the cookie remains after closing various browsers and reopening them. I discovered that there were problems when using a format like `"15 Jul 2012"`. This format worked for me during development in Firefox, but other browsers only seemed to set the cookie as a session cookie. Should I stick to using just this format: `"Sun, 15 Jul 2012 00:00:01 GMT"` or are there other formats I could use for the expiry date that will work across the major browsers (IE 7-9, Firefox, Chrome, Opera, Safari)?

Original source