Microsoft has increased the number of cookies web sites can deposit on users’ computers from 20 to 50 in the latest updates to Internet Explorer 7, bringing it into line with the rival Firefox browser.
This change was made to simplify the development and hosting of web applications on domains that use a large number of cookies, IE program manager Eric Law wrote on a Microsoft blog late last week.
Cookies are small text strings web sites use to identify users within and between sessions. As web applications become more complex, often more state data needs to be stored in cookies, and there are an increasing number of HTTP requests.
Microsoft’s law suggested using the shortest cookies possible: For instance, rather than naming a cookie USERNAME, name it U. The seven bytes saved might not sound like much, but multiplied over dozens or hundreds of requests, these savings can add up.
Developers can also store heavy embedded objects on a secondary domain that uses shorter cookies than the primary domain, or configure their servers to only check cookies on certain directory paths, Law said.
Firefox is understood to already support up to 50 cookies per domain.
The Internet Engineering Task Force RFCs which standardize the cookie format only set minimum limits – 20 cookies per domain, with a minimum size of 4,096 bytes per cookie – so the changes to IE7 keep the browser standards-compliant.