Dynamic HTML: The Definitive Reference

Name

cookie — NN 2 IE 3 DOM 1

Synopsis

Read/Write

The HTTP cookie associated with the domain of the document and stored on the client machine in the “cookie file.” Reading and writing the cookie property are not parallel operations. Reading a cookie property returns a semicolon-delimited list of name/value pairs in the following format:

name=value

Up to 20 of these pairs can be stored in the cookie property for a given domain (regardless of the number of HTML documents used in that web site). A total of 4,000 characters can be stored in the cookie, but it is advisable to keep each name/value pair to less than 2,000 characters in length. It is up to your scripting code to parse the cookie property value for an individually named cookie’s value.

Writing cookie property values allows more optional pairs of data associated with a single name/value pair. The format is as follows:

document.cookie = "name=value
    [; expires=timeInGMT]
    [; path=pathName]
    [; domain=domainName]
    [; secure]"

No matter how many optional subproperties you set per cookie, only the name/value pair may be retrieved. All cookie data written to the cookie property is maintained in the browser’s memory until the browser quits. If an expiration date has been made part of the cookie data and that time has not yet expired, the cookie data is saved to the actual cookie file; otherwise, the cookie data is discarded. The browser automatically deletes cookie data that has expired when the browser next starts.

Example

var exp = new ...