<meta> element

The <meta> element provides meta information for a WML deck. This element is specified within the deck header along with any access control information for the deck (for more information, see <access> element and <head> element). Note that not all devices support every meta information type.

Syntax

Attributes

 
property
(required) 		 You must specify one of the following attributes: 

name="name"
http-equiv="name"

  • If you specify the name attribute, the UP.Link Server ignores the metadata. 
  • If you specify the http-equiv attribute, the UP.Link Server converts the metadata to an HTTP response header. 
content Specifies the metadata value associated with the property attribute. 
scheme The UP.Browser software does not currently support this attribute. 
forua true | false 

Specifies that the author intended the property to reach the user agent. If forua="false", an intermediate agent must remove the <meta> element before the document is sent to the client. If the value is "true", the metadata of the element must be delivered to the user agent. The method of delivery may vary. For example, http-equiv metadata may be delivered using HTTP or WSP headers. 

 

Cache control

Like conventional Web browsers, the UP.Phone has a memory cache. It caches each deck that the user visits in order to quickly redisplay it without requesting it from the UP.Link Server again. The length of time that a device keeps a deck in cache is called the time to live (TTL). The default UP.Phone TTL is 30 days (or until memory is exhausted). If a deck contains time-sensitive information, you can specify a shorter TTL so that the device will reload the deck from the server more frequently. The following example illustrates how to use a <meta> statement to set the TTL: The max-age parameter specifies the time (in seconds) to cache the deck. The example above instructs the device to drop the deck from the cache after 1 hour (3600 seconds). To determine the right TTL for a deck, you should balance the time-sensitivity of the information with the degradation in response time caused by reloading information from the server. Setting max-age to zero causes the UP.Browser to reload the deck every time the user navigates to it in a forward direction; however, if the user navigates back to the deck, the UP.Browser displays the card from the information in cache.

The UP.Browser now performs "if-modified-since" content negotation with the HTTP server, but only after a deck's TTL has expired. Decks may now specify "no-cache" in the Cache-control <meta> element, which is equivalent to "max-age=0." Decks may also specify "must-revalidate" in the Cache-control <meta> element, which forces the UP.Browser to revalidate the deck's TTL, even if the user navigates to the deck in the backward direction. Finally, if the Cache-control <meta> tag is not defined in the WML deck, the browser may derive the deck's TTL from the HTTP cache headers, based on the HTTP/1.1 caching model.

Bookmarks

UP.Phone bookmarks are similar to conventional Web browser bookmarks. When a user bookmarks a card, the UP.Browser creates a bookmark that consists of two items: Because all decks are now bookmarkable by default, the markable <meta> element is only used to turn off bookmarking for a deck. The syntax for the statement is as follows: When a user bookmarks a card, the UP.Browser automatically sets the bookmark URL to the URL for the deck. If you want to use a different URL, you can specify another <meta> element in the deck header using the following syntax: where url is the URL you want to use for the bookmark.