Indicates to an application the intended behavior for a link, specifically, the timing for obtaining or retrieving the content of a link (e.g., by a user clicking on the link to “request” the material, or by the material being automatically loaded with an article when the article is loaded)
| Value | Meaning | 
|---|---|
| none | The behavior is unconstrained, and no other markup is generally available in the link to assist an application in deducing the retrieval mechanism. | 
| onLoad | An application should retrieve the link at the same time a user obtains the initial article. | 
| onRequest | An application should only retrieve the link after a user has physically triggered the retrieval, e.g., clicked on the link. | 
| other | The behavior is unconstrained, but other markup is generally available in the link to assist an application in deducing the retrieval mechanism. | 
| Restriction: This attribute may be specified if the element is used. | |