The address for a specific web page, file, or other resource on the web is called a URL, or Uniform Resource Locator. Some people prefer the term URI, or Uniform Resource Identifier – which is probably more accurate — the address of a web page describes what it is, not really where it is.
There are important technical distinctions between the two different names, but most people use them interchangeably, which is fine. The important thing is to know what people are talking about. When someone says “URL” or “URI,” they are talking about the web address of a page, document, file, or other resource.
Everything on the web has a URL, and they are all unique (that’s the “U”). Every page you visit online, as well as every image, video, audio file, script, and stylesheet has its own URL.
The Parts of a Web Address
A URL, or web address, has a few different parts:
http://— The protocol. Most of the time, this will either behttp(Hyper Text Transfer Protocol) orhttps(HTTP over SSL — the secure version of HTTP). HTTP is the standard protocol for web pages and similar content.example.com— The domain name. This tells your browser where to send the request (see details on the Domain Name System, below)./page-name— The path. What follows the first slash (/) after the domain name is the path. This specifies the files, script, or other resource on the hosting computer. If there is no path (the URL is justhttp://example.com), then that is usually the home page of the domain.- Some addresses have additional parameters. These are variables that are added after the path. They are separated from the path by a question mark (
?), like this:http://example.com/path-name?color=blue&shape=triangle. In this example,colorandshapeare both parameters with valuesblueandtriangle. - Some address may also have a named anchor. This is a reference to a specific place in the resource — either a section (in the case of a text document) or a time stamp in video or audio. The named anchor comes last in a URL, and is preceded by the hash or octothorpe (
#) sign. For example:#anchor-name.
Domain Names & IP Addresses
The hostname, or domain name, is resolved to an IP address by the Domain Name System, or DNS. Domain names are human readable and meaningful, but not understandable to computers.
Every computer has an IP Address — a unique identifier that allows other computers to find it and communicate with it. The DNS system is like a giant, distributed phone book that provides IP addresses for every domain name.
This happens in the background — your browser takes care of it and you never have to worry about it.
Identifying URLs Without Clicking on Them
When you are looking at a web page, and you hover over a hyperlink, the URL of the linked page appears in the bottom left corner of your browser. (This is the case with most browsers.) This gives you an opportunity to see where you are going before you click on it. You can also right-click (two-finger-tap) and click “Copy Link Address” if you want to be able to paste the URL without actually loading the page.