Web - URL

An Uniform Resource Locator (URL) is a universal identifier for a resource.

It's the string that is understood by a browser when you put it in the address bar.

When the HTTP protocol is used as scheme, it's a identifier for a Web resource.

An URL was originally created to provide a method for finding an item such as a person's street address.

On a format level, the URL is a subset of an URI.

scheme://[[email protected]]host[:port]/path?query#fragment

where:

• scheme is the scheme and defines the access protocol that can be:
  • http or https defines the HTTP protocol (and we will make HTTP request)
  • file defines the local file system (and will make call to the local OS)
• user-info is optional and defines the credential (not used with the file scheme)
• host[:port]] defines the endpoint (not used with the file scheme)
• path is the path to the resource
• query is the query string
• fragment is the fragment that identify a part in the resource.

See URL - URL Rewrite

See URL - URL encoding (Percent-encoding)

Lowest common denominator max URL length among popular web browsers is 2100 (Reference

The value is stored in the href property

• We used window.parent because the code is run in a iframe but in a normal page, you would just use window.

console.log("URL: "+window.parent.location.href); // url
// value is `about:srcdoc` because we are in a iframe
console.log("URL in iframe: "+window.location.href);

• Path

console.log("Path: "+window.parent.location.pathname);

• host is the endpoint ie hostname and port (if not the default HTTP port)

console.log("Host: "+window.parent.location.host); 

• hostname - only the name of the host (ie without the port)

console.log("Hostname: "+window.parent.location.hostname); 

• fragment

console.log("Anchor: "+window.parent.location.hash);  

• port (empty string if none)

console.log("Port: "+window.parent.location.port);  

• protocol

console.log("Protocol: "+window.parent.location.protocol); 

• query string ?key=value

console.log("Query String: "+window.parent.location.search);

• W3C URL specification
• The W3C URL specification defines the term URL, various algorithms for dealing with URLs, and an API for constructing, parsing, and resolving URLs.
• HTML5 URL parsing