URI Scheme Prefix

Web & Network

Matches the scheme part of a URI per RFC 3986.

/^[a-zA-Z][a-zA-Z0-9+.-]*:/

How it works

URI schemes must start with a letter, then alphanumerics or + . -. Useful to detect arbitrary URI prefixes (http, https, file, custom:, data:, javascript:, mailto:).

Test Cases

Should Match

http://
javascript:alert(1)
myapp+xml:foo
x-callback-url:

Should NOT Match

1http:
://
no-scheme

Quick Summary

Matches the scheme: prefix of a URI per RFC 3986. Useful for cross-protocol detection.