There’s more than just two letters difference. In fact, you can’t really compare them at all. But you can use them together.
HTML stands for Hypertext Markup Language. A well formatted HTML document though is really nothing more than a special XML document that uses certain tags. It starts out with an opening tag called html and ends with a closing html tag. Inside this, you’ll find a section enclosed with tags called head and another section enclosed with tags called body. Most of what you see in your web browser is inside the body section.
You can surround text with p tags to create paragraphs, h1 tags to create a large heading, a tags to create a link that points to another HTML document, and img tags to display images. The browser uses these tags and many more to figure out how to display the document. It doesn’t display the tags themselves and instead you can think of the tags as instructions to the browser.
You can create an HTML file in a text editor and save it locally on your computer. Then you can open it with your browser to view it. While this works, it’s not the way we normally get HTML files into our browsers. We normally visit web sites and what’s really happening is that the browser is requesting HTML files as well as other files from the web site. Once it has the files, it can display them. And that’s where HTTP comes into the picture.
HTTP stands for Hypertext Transfer Protocol. This defines how HTML and other files are transferred to and from computers.
This episode describes the following five aspects of HTTP with some examples along the way.
- HTTP is based on a series of requests and responses.
- HTTP identifies computers and files on those computers with URLs.
- HTTP defines methods or verbs as they’re sometimes called that you specify in your request.
- HTTP defines well known status codes.
- HTTP is stateless.
Make sure to listen to the full episode or read the full transcript below for more details and some examples.
Transcript
Before getting too far into distributed computing, I thought it would be good to explain some basics for how one of the most distributed network works, the World wide Web or WWW. There’s a lot more to this than I can explain in this episode. For now, I just want to focus on two things, HTML and HTTP.
Why should you be interested? What are they? How are they used? And how do they influence distributed computing?
HTML and HTTP work together to form the backbone of the world wide web. And that forms a huge distributed computing network.
A lot of people who are learning to code are introduced to HTML and CSS. I’ll explain CSS in a future episode. The main thing is that these are not programming languages. They’re ways to format and present information. In other words, it’s just data with some instructions for how that data should look when presented in a web browser. You can add some JavaScript and then you have the ability to program.
HTML stands for Hypertext Markup Language. And this probably lends some credibility to this being a language. A well formatted HTML document though is really nothing more than a special XML document that uses certain tags.
It starts out with an opening tag called html and ends with a closing html tag. Inside this, you’ll find a section enclosed with tags called head and another section enclosed with tags called body. Most of what you see in your web browser is inside the body section.
You can surround text with p tags to create paragraphs, h1 tags to create a large heading, a tags to create a link that points to another HTML document, and img tags to display images.
The browser uses these tags and many more to figure out how to display the document. It doesn’t display the tags themselves and instead you can think of the tags as instructions to the browser.
You can create an HTML file in a text editor and save it locally on your computer. Then you can open it with your browser to view it. While this works, it’s not the way we normally get HTML files into our browsers. We normally visit web sites and what’s really happening is that the browser is requesting HTML files as well as other files from the web site. Once it has the files, it can display them. And that’s where HTTP comes into the picture.
HTTP stands for Hypertext Transfer Protocol. This defines how HTML and other files are transferred to and from computers.
I’ll describe five aspects of HTTP with some examples along the way.
The first aspect is that HTTP is based on a series of requests and responses. A server isn’t going to send you anything unless you first ask for it. And even then, it’s not going to send you something and then send you something else. One computer makes a request, and the other computer responds to that request.
How do you know which computer to make a request from? That’s the next aspect. HTTP identifies computers and files on those computers with URLs. You’re probably familiar with internet domain names. Well, a full URL will look something like https://www.takeupcode.com/offers I’ll make a future episode just for URLs. These form the links between web pages on the internet and give the hypertext in HTML and HTTP their meaning.
Alright, so you know how to identify a server and now know that you need to make a request before you can get a response, but what can you request? That’s the next aspect. HTTP defines methods or verbs as they’re sometimes called that you specify in your request. And by this, I mean your browser normally formats the requests for you with these verbs. You don’t have to know what they are when you click on a link in your browser and a new page opens and gets displayed. But you should know about them if you want to understand how HTTP works. There are many verbs. Here are four of them.
◦ Get is used to request that the server return what you’re asking for. this is the most common verb and is used anytime your browser wants to get a web page to display.
◦ Post and Put are two similar verbs used to send information to a server. Anytime you add a comment to a blog or social media site, you’re using one of these verbs.
◦ Delete is used to delete information from a server. I don’t mean that you delete a web page although that could happen. It’s normally used to delete some data displayed. Maybe you decide to remove an item from your shopping cart, you’re probably using this verb.
◦ I’ll go into more depth about these verbs later in a future episode.
So you’ve made a request and the server is sending its response. How do you know if your request was successful or not? That’s the next aspect. Status codes are well defined number values that HTTP defines. For example, 200 means everything is okay. Why 200? Well, why not. The numbers are grouped together to give some organization. But other than that, they’re just some numbers that HTTP defines to have special meaning.
And the final aspect I’ll explain is that HTTP is stateless. This means that when you make a request and get a response, then there’s nothing that carries over into another request and response. That doesn’t mean that the server can’t remember who you are. If that was the case, then you’d never be able to shop for different items or even a single item and make it to a checkout page with your selection to complete the purchase. Obviously, servers are able to remember some information about your previous requests. But they do that with other means. HTTP doesn’t provide this ability. Until recently, the entire connection between the requesting and responding computers would end completely after each and every response. We at least have the ability now to keep a connection open.