Meaning of URL, a Uniform Resource Locator is a way to identify the location of a file on the Internet. They are what we use not only to open websites, but also to download images, videos, software programs and other types of files hosted on servers.
Opening a local file on your computer is as easy as double-clicking on it, but to open files on remote computers such as a web server, we must use the URL so that our web browser knows where to look. , For example, as described below, opening an HTML file representing a web page is done by entering it in the navigation bar at the top of the browser you are using.
How to use URL ?
Any URL can be typed inside the address bar of the browser to access the resource behind it. But this is only the tip of the iceberg!
The HTML language – which will be discussed later – makes extensive use of URLs :
- To create links to other documents with the <a> element.
- To link a document to its related resources through various elements such as <link> or <script>.
- To display media such as images (with the <img>element) , videos (with the <video> element), sound and music (with the <audio> element), etc.
- To display other HTML documents with the <iframe> element.
Get information about the structure of URLs:
A URL can be broken down into separate sections, each piece serving a specific purpose when accessing a remote file.
HTTP and FTP URLs are structured similarly to protocol://hostname/fileinfo. For example, accessing an FTP file by its URL might look something like this :
Which, apart from being FTP instead of HTTP, looks like any other URL you might encounter on the web.
Let’s use the following URL as an example of an HTTP address and identify each part :
- https is a protocol (like ftp is a protocol) that defines the type of server you are communicating with.
- Security is the hostname used to access this specific website.
- googleblog is the domain name. ex- .com are called top-level domains (TLDs), some of which include .net, .org, .co.uk, etc.
- /2018/01/ Represents the directories used to organize the web page or file. On the web server that holds the website files, these will be the actual folders that you click to locate the file specified by this URL.
- Todays-cpu-vulnerability-what-you-need.html is the actual file the URL is pointing to. If you were trying to load an image, audio file, or other file type instead of an HTML file, the URL would end in that file extension (such as PNG or MP3).
- Security.googleblog.com as a group is called a fully qualified domain name (FQDN).
More info on URL
If a URL points you to a file that your web browser can display, such as a JPG image, you don’t actually need to download it to your computer to view it. However, for files that are not normally displayed in the browser, such as PDF and DOCX files, and EXE files in particular (and many other file types), you will be prompted to download it.
URLs provide an easy way for us to access a server’s IP address without knowing what the actual address is. They’re like easy-to-remember names for our favorite websites. It is the translation from URL to IP address for which DNS server is used.
Some URLs are really long and complicated and are best used if you click on it as a link or copy/paste it into the browser’s address bar. A mistake in the URL can produce a 400-series HTTP status code error, the most common type being a 404 error.
If you try to access a page that does not exist on the server, you will receive a 404 error. These types of errors are so common that you will often find custom, often humorous, versions of them on some websites. If you’re having trouble accessing a website or online file that you think should load normally, try troubleshooting the URL.
Most URLs do not require a port name. Opening google.com, for example, can be done by specifying its port number at the end like http://www.google.com:80 but this is not required. If the website was working on port 8080 instead, you can change the port and access the page that way.
By default, FTP sites use port 21, but others can be set to port 22 or something different. If the ftp site is not using port 21, you must specify which one it is using in order to access the server correctly. The same concept applies to any URL that uses a different port than the one used by the program by default.