Mailto

Last updated

mailto is a Uniform Resource Identifier (URI) scheme for email addresses. It is used to produce hyperlinks on websites that allow users to send an email to a specific address directly from an HTML document, without having to copy it and entering it into an email client.

Contents

It was originally defined by Request for Comments (RFC) 1738 in December 1994, [1] expanded by RFC 2368 in July 1998, [2] and refined by RFC 6068 in October 2010. [3]

Examples

"mailto" can be used within an HTML document to generate a link for sending email:

<ahref="mailto:someone@example.com">Send email</a>

Clicking on the hyperlink automatically opens the default email client, with the destination email address pre-filled.

It is possible to specify initial values for headers (e.g. subject, cc, etc.) and message body in the URL. Blanks, carriage returns, and linefeeds cannot be directly embedded but must be percent-encoded: [4] 

<ahref="mailto:someone@example.com?subject=This%20is%20the%20subject&cc=someone_else@example.com&body=This%20is%20the%20body">Send email</a>

Multiple addresses can be specified: [3] 

<ahref="mailto:someone@example.com,someoneelse@example.com">Send email</a>

The address can be omitted:

<ahref="mailto:?subject=mailto%20with%20examples&body=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FMailto">Share this knowledge...</a>

Only the initial header must use a question mark (?) prepended. All subsequent headers require an ampersand (&). Should this not be the case, the scheme will not properly copy over the headers to the email client. [5]

Security and privacy

A number of security issues are mentioned in RFC 6068, one of them being robotic address harvesting. Mailto constructs are locatable within HTML pages by automated means which typically include the use of DOM constructs or regular expressions. Addresses harvested by such means are liable to be added to spammers' mass-mailing lists and thus to receive large amounts of unwanted mail.

While methods exist to "harden" mailto links against harvesting—address munging and JavaScript-based address obfuscation among them—these protections can be circumvented by sufficiently sophisticated harvesting robots. Other techniques, like walling the address behind a CAPTCHA or similar "humanity check", provide security on par with that available for other contact methods, most notably web forms, which experience similar challenges with preventing spam.

Related Research Articles

<span class="mw-page-title-main">Email</span> Mail sent using electronic means

Email is a method of transmitting and receiving messages using electronic devices. It was conceived in the late–20th century as the digital version of, or counterpart to, mail. Email is a ubiquitous and very widely used communication medium; in current use, an email address is often treated as a basic and necessary part of many processes in business, commerce, government, education, entertainment, and other spheres of daily life in most countries.

Multipurpose Internet Mail Extensions (MIME) is a standard that extends the format of email messages to support text in character sets other than ASCII, as well as attachments of audio, video, images, and application programs. Message bodies may consist of multiple parts, and header information may be specified in non-ASCII character sets. Email messages with MIME formatting are typically transmitted with standard protocols, such as the Simple Mail Transfer Protocol (SMTP), the Post Office Protocol (POP), and the Internet Message Access Protocol (IMAP).

The Simple Mail Transfer Protocol (SMTP) is an Internet standard communication protocol for electronic mail transmission. Mail servers and other message transfer agents use SMTP to send and receive mail messages. User-level email clients typically use SMTP only for sending messages to a mail server for relaying, and typically submit outgoing email to the mail server on port 587 or 465 per RFC 8314. For retrieving messages, IMAP is standard, but proprietary servers also often implement proprietary protocols, e.g., Exchange ActiveSync.

A Uniform Resource Identifier (URI), formerly Universal Resource Identifier, is a unique sequence of characters that identifies an abstract or physical resource, such as resources on a webpage, mail address, phone number, books, real-world objects such as people and places, concepts. URIs are used to identify anything described using the Resource Description Framework (RDF), for example, concepts that are part of an ontology defined using the Web Ontology Language (OWL), and people who are described using the Friend of a Friend vocabulary would each have an individual URI.

A Domain Name System blocklist, Domain Name System-based blackhole list, Domain Name System blacklist (DNSBL) or real-time blackhole list (RBL) is a service for operation of mail servers to perform a check via a Domain Name System (DNS) query whether a sending host's IP address is blacklisted for email spam. Most mail server software can be configured to check such lists, typically rejecting or flagging messages from such sites.

An email address identifies an email box to which messages are delivered. While early messaging systems used a variety of formats for addressing, today, email addresses follow a set of specific rules originally standardized by the Internet Engineering Task Force (IETF) in the 1980s, and updated by RFC 5322 and 6854. The term email address in this article refers to just the addr-spec in Section 3.4 of RFC 5322. The RFC defines address more broadly as either a mailbox or group. A mailbox value can be either a name-addr, which contains a display-name and addr-spec, or the more common addr-spec alone.

Various anti-spam techniques are used to prevent email spam.

Sender Policy Framework (SPF) is an email authentication method which ensures the sending mail server is authorized to originate mail from the email sender's domain. This authentication only applies to the email sender listed in the "envelope from" field during the initial SMTP connection. If the email is bounced, a message is sent to this address, and for downstream transmission it typically appears in the "Return-Path" header. To authenticate the email address which is actually visible to recipients on the "From:" line, other technologies such as DMARC must be used. Forgery of this address is known as email spoofing, and is often used in phishing and email spam.

URL redirection, also called URL forwarding, is a World Wide Web technique for making a web page available under more than one URL address. When a web browser attempts to open a URL that has been redirected, a page with a different URL is opened. Similarly, domain redirection or domain forwarding is when all pages in a URL domain are redirected to a different domain, as when wikipedia.com and wikipedia.net are automatically redirected to wikipedia.org.

A query string is a part of a uniform resource locator (URL) that assigns values to specified parameters. A query string commonly includes fields added to a base URL by a Web browser or other client application, for example as part of an HTML document, choosing the appearance of a page, or jumping to positions in multimedia content.

MHTML, an initialism of "MIME encapsulation of aggregate HTML documents", is a Web archive file format used to combine, in a single computer file, the HTML code and its companion resources that are represented by external hyperlinks in the web page's HTML code. The content of an MHTML file is encoded using the same techniques that were first developed for HTML email messages, using the MIME content type multipart/related. MHTML files use an .mhtml or .mht filename extension.

<span class="mw-page-title-main">HTTP referer</span> HTTP header field

In HTTP, "Referer" is an optional HTTP header field that identifies the address of the web page from which the resource has been requested. By checking the referrer, the server providing the new web page can see where the request originated.

The SIP URI scheme is a Uniform Resource Identifier (URI) scheme for the Session Initiation Protocol (SIP) multimedia communications protocol. A SIP address is a URI that addresses a specific telephone extension on a voice over IP system. Such a number could be a private branch exchange or an E.164 telephone number dialled through a specific gateway. The scheme was defined in RFC 3261.

MicroID is a decentralized identity protocol. It was originally developed in 2005 by Jeremie Miller. A MicroID is a simple identifier comprising a hashed communication/identity URI and claimed URL. Together, the two elements create a hash that can be claimed by third-party services.

Domain-based Message Authentication, Reporting and Conformance (DMARC) is an email authentication protocol. It is designed to give email domain owners the ability to protect their domain from unauthorized use, commonly known as email spoofing. The purpose and primary outcome of implementing DMARC is to protect a domain from being used in business email compromise attacks, phishing email, email scams and other cyber threat activities.

Email forwarding generically refers to the operation of re-sending a previously delivered email to an email address to one or more different email addresses.

The Abuse Reporting Format (ARF) also known as the Messaging Abuse Reporting Format (MARF) is a standard format for reporting spam via email.

<span class="mw-page-title-main">HTTP location</span> Instruction by web server containing the intended location of a web page.

The HTTP Location header field is returned in responses from an HTTP server under two circumstances:

  1. To ask a web browser to load a different web page. In this circumstance, the Location header should be sent with an HTTP status code of 3xx. It is passed as part of the response by a web server when the requested URI has:
  2. To provide information about the location of a newly created resource. In this circumstance, the Location header should be sent with an HTTP status code of 201 or 202.

A uniform resource locator (URL), colloquially known as an address on the Web, is a reference to a resource that specifies its location on a computer network and a mechanism for retrieving it. A URL is a specific type of Uniform Resource Identifier (URI), although many people use the two terms interchangeably. URLs occur most commonly to reference web pages (HTTP/HTTPS) but are also used for file transfer (FTP), email (mailto), database access (JDBC), and many other applications.

Larry Melvin Masinter is an early internet pioneer and ACM Fellow. After attending Stanford University, he became a Principal Scientist of Xerox Artificial Intelligence Systems and author or coauthor of 26 of the Internet Engineering Task Force's Requests for Comments.

References

  1. ↑ Berners-Lee, T.; Masinter, Larry; McCahill, M. (December 1994). "Uniform Resource Locators (URL)" . Retrieved 11 September 2021.
  2. ↑ Hoffman, Paul; Masinter, Larry; Zawinski, Jamie (July 1998). "The mailto URL scheme" . Retrieved 26 September 2015.
  3. 1 2 Duerst, Martin; Masinter, Larry; Zawinski, Jamie (October 2010). "The 'mailto' URI Scheme" . Retrieved 26 September 2015.
  4. ↑ "Creating hyperlinks § E-mail links". MDN Web Docs. Retrieved 2019-09-30.
  5. ↑ "RFC 6068". IETF Datatracker.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.