The HTML <iframe> longdesc Attribute is used to specify a page that contains the long description of the content of the iframe element.
- URL: It contains single value i.e URL which specify the page which contains the long description of the content of the frame.
- An absolute URL: It points to another website.
- A relative URL: It points to a file within a website.
Supported Browsers: The major browsers are not supported by HTML <iframe> longdesc Attribute.