The <a> tag is used to define a hypertext link.
href attribute
If the value of the href attribute is a URL, it may contain any of the following components:
2)
If the protocol scheme, host name/IP address and port number are omitted the default is the current host - the same server handling the current document. If the path starts with a slash /..., it is an absolute path from the base of the current document, which defaults to the document root directory on the server. A URL with a "#" but no fragment identifier points to the top of the document.
<a href="#">back to top</a><a href="another-page.html">another page</a><a href="/another-section/">another section</a><a href="http://www.ExampleOnly.com/">Example Only</a>
id attribute
The id attribute
common attributes
In addition to the attributes above, which are specific to the <a> tag, any of the common HTML attributes can also be used.
The rel values for the <a> tag are:
Links to an alternate representation of the document. For example:
Links to previously created versions of related documents, such as the archives of a blog.
Links to a document about the author of the document in which the link tag appears.
Provides a permanent link to the document or a section within the document.
Links to a document with contact information.
Indicates that the link is to a resource on a different web site.
Links to a syndicated feed channel for the document or the web site.
Links to the first document in a series of articles.
Links to an index document or a table of contents for the collection of documents that includes the document in which the link tag appears.
Links to the last document in a series of articles.
Links to a document that describes the copyright license that applies to the document(s) in which the link to the license page appears.
Links to the next document in sequence.
Indicates to search engine crawlers and other robots that they should not follow the link to the referenced resource and process the document there. This can be used to indicate that the linked document should not be considered to be a recommended resource when determining the search engine rank for the linked page. This may help the page where the link appears from being penalized for "recommending" less desirable pages, such as for links to an affiliate site.
Indicates that the user agent should not identify the referring page to the server handling the request for the target page. If this value is omitted or ignored, the URL of the page containing the link will most likely be included in the Referer[sic] header of the HTTP request for the referenced page.
Links to the previous document in the series.
Links to a search page for the web site or a subset of documents that includes the document in which the search link appears.
Indicates that the referenced document should be loaded into the web browser's sidebar if the link is activated by the user.
Specifies a URI that is a "tag", which describes the subject of a page. The tag may be a URL, which leads to a web-accessible page, or just a standalone identifier.
Links to the document at the next higher level in a tree hierarchy.
<a href=""></a>
<a href="tel:+17775551234">Call Me at +1-777-555-1234</a>
The media attribute has been added for consitency with the <link> tag
The following attributes should not be coded on the <script> tag because they either have been deprecated or were never officially supported:
In HTML 5, you can put the <a> tag around block elements in addition to inline elements. This means that links can appear where they couldn't before. For example, you can turn a whole HTML table row into a link:
<table> <tr><td>Label:</td><td>Data...</td></tr> ... <tr onclick="location=this.getElementsByTagName('a')[0]"> <a href="new-row.html"/> <td colspan="2">Add a Row</td> </tr></table>