Thescheme of a URI is the first part of the URI, before the: character.It indicates which protocol the browser must use to fetch the resource.The scheme may affect how the rest of the URI is structured and interpreted.

Syntax

protocol:

protocol

A sequence of characters that identifies the protocol to use.It should consist of only alphanumeric characters and the+,-, and. characters.Common schemes are:

blob

Binary Large Object; a pointer to a large in-memory object

data

Data directly embedded in the URL

file

Host-specific file names

ftp

File Transfer Protocol

http /https

Hypertext Transfer Protocol (and secure connections)

javascript

URL-embedded JavaScript code

mailto

Electronic mail address

resourceNon-standard

For Firefox and Firefox browser extensions to load internal resources

ssh

Secure shell

tel

Telephone

urn

Uniform Resource Names

view-source

Source code of the resource

ws /wss

WebSocket connections (and secure connections)

Description

Consider the following URL:

http://www.example.com:80/path/to/myfile.html?key1=value1&key2=value2#SomewhereInTheDocument

http is thescheme of the URL, indicating which protocol the browser must use. Usually it is the HTTP protocol or its secured version, HTTPS. The Web requireshttp orhttps, but browsers can open URIs with other schemes, like those that start withmailto: (to open a mail client) orftp: (file transfers).

When using URLs inHTML content, you generally only use a few of these URL schemes. When referring to subresources — that is, files that are being loaded as part of a larger document — you should only use the HTTP and HTTPS schemes. Increasingly, browsers are removing support for using FTP to load subresources, for security reasons.

FTP is still acceptable at the top level (such as typed directly into the browser's URL bar, or the target of a link), although some browsers may delegate loading FTP content to another application.

Examples

Different URI schemes

The following example shows different URI formats based on URI scheme.

tel:+1-816-555-1212git@github.com:mdn/browser-compat-data.gitftp://example.org/resource.txturn:isbn:9780141036144mailto:help@supercyberhelpdesk.info

Specifications

See also

• URIs
• Data URLs
• Resource URLs
• IANA list of URI schemes