So, when you type a website address and press Enter, a bunch of tech stuff happens behind the scenes. People often ask IT experts about this in interviews to see how much they know. But don't worry, I can explain it in simple terms!
Imagine you're about to visit a website. It's not just a direct jump—it's like a journey with many technologies working together. These technologies make sure your online experience is both easy and safe. Cool, right?
When you type a web address into your browser, that address is called a Uniform Resource Locator, or URL for short. Think of it like a unique ID for something on the internet, usually a specific webpage. But keep in mind, sometimes it might not always be a webpage we're talking about.
When you open your browser and go to a website, it first looks in its memory to see if it already has some information about that site saved. This is like a shortcut to save time.
If the browser has the information and it's still good, it uses that saved data. If not, it looks at the website's address (URL), which has parts like http or https (which you don't need to worry too much about), the name of the site (like focus21.io), and maybe a specific page on the site.
Sometimes, your browser helps you out by suggesting website addresses based on what you've typed before or what sites you've saved. It does this by trying to guess what you're going to type next, using fancy computer algorithms. It's like when your phone predicts the next word when you're texting.
So, the browser is like a smart friend trying to help you visit websites quickly and easily, using its memory and some clever guessing.
When you type a website's name in your browser, it needs to find where that website is on the internet. It asks the Domain Name System (DNS), which is like a big address book. The DNS translates the website's name into a special number called an IP address. This number is like the website's home address on the internet, helping your browser reach the right place.
First, your device checks if it already knows the website's address. If it does, great! If not, the question goes to DNS servers, starting with your Internet Service Provider's (ISP) special helper called a recursive resolver.
If the resolver doesn't know, it asks the main DNS boss (root DNS server), which points to specific servers for different types of websites (like .com or .org). Those servers know the exact address and send it back to your device through the recursive resolver.
This whole process happens super fast, in just a few milliseconds. And to keep things safe, it also includes some encryption tech to protect against online baddies.
Once the website's IP address is identified through DNS, the browser is ready to establish a connection with the server hosting the desired site. However, before data transmission begins, a series of actions resembling a three-way handshake takes place between the device and the server.
This three-way handshake refers to the Transmission Control Protocol (TCP) — a protocol ensuring that both communication participants (in this case, a browser on any device and the server) are prepared for data exchange, the channel is reliable, and the entire process is 100% secure.
Three basic steps are executed:
Yet, that's not all. Another crucial step is establishing a secure connection. If you see "https" at the beginning of the URL (instead of just "http"), it indicates that the website employs the SSL/TLS security protocol. It ensures that all data transmitted between the browser and server is encrypted and cannot be intercepted.
Once a connection is established, the browser sends an HTTP request to the server. It contains information about the specific page or resource needed, as well as various additional parameters such as the preferred language of the page or the types of data the device can process.
This request might also include cookies—small data fragments that a website stores on the device. They assist the server in remembering a specific user, which proves especially useful for functions like system logins, shopping carts, and providing personalized content.
When the server receives the request, it might simply deliver the requested page or resource. However, it often also performs several supplementary tasks. For instance, server-side code might determine which database information to display or generate dynamic content.
The server sends a response back to the browser. This includes a status (for instance, 200 signifies a successful process, whereas 404 indicates the requested page wasn't found). Furthermore, the response contains the requested data, which could be an HTML page, image, video, etc.
Initially, the browser analyzes the HTML—the primary markup language used to establish web page structure. During this process, it constructs a tree of the so-called DOM (Document Object Model), representing the hierarchical structure of every element on the particular page.
Post the HTML parsing, the browser begins applying styles from CSS to determine the appearance of each element: its size, colour, positioning, and much more. These styles can be defined within the document itself, in separate files, or directly within element attributes.
While the page's main structure and styles are already processed, media resources like images, videos, and audio might still be loading. Modern browsers are optimized for parallel resource loading, accelerating content display.
In summary, what appears on the screen when visiting a specific website is the result of an intricate interpretation process executed by the browser. The average user doesn't need to delve deeper into this process. Let's leave that to IT professionals specializing in digital business transformations.